That set up a dizzying week of attacks in Lebanon. Israel blew up electronic devices distributed by Hezbollah, killing dozens of people and injuring thousands more. It then assassinated a group of its military leaders in an airstrike near Beirut. On Monday, a wave of Israeli airstrikes targeting parts of the country where Hezbollah holds sway killed hundreds of people.

The intensified attacks against Hezbollah reflects the opinion of some hawkish generals and others who think that the group can be forced to back down, the officials said, while others in the government believe Israel must first come to a deal on a cease-fire and hostage deal with Hamas before turning to another battleground. Prime Minister Benjamin Netanyahu has opposed a truce that would allow Hamas to survive the war.

The decision to escalate was met with strong opposition from some senior officials, according to three current and former officials who spoke to The Times. They worried that such actions, the officials said, could lead to all-out war with face-to-face fighting and questioned how they would pave the way for the return of Israelis to the north.

Hezbollah has been targeting northern Israel with rockets and drones since last year in solidarity with Hamas and its war against Israel in Gaza. Hassan Nasrallah, the Hezbollah leader, has said the group will not agree to stop firing at Israel until Israel and Hamas reach an agreement that ends the war in Gaza.

The Israeli military says that Mr. Qobeisi planned the abduction of three Israeli soldiers in 2000; their bodies were later returned to Israel in a prisoner exchange.

Israel has stepped up efforts to assassinate Hezbollah’s top leaders in recent weeks as part of a campaign to compel the Iranian-backed militant group to stop firing rockets and drones at Israel. For nearly a year, Hezbollah has been attacking Israel in solidarity with Hamas in Gaza, displacing tens of thousands of Israelis from border communities.

The campaign against the top echelon in Hezbollah comes after months of attacks that, Israeli military analysts said, have somewhat degraded Hezbollah’s military capabilities.

Over the past two months, Israel has killed at least two members of Hezbollah’s top military decision-making body, the Jihad Council, and tried to assassinate another.

In July, an Israeli airstrike in Beirut’s southern suburbs killed Fuad Shukr, one of the leaders of Hezbollah’s military operations and a confidante of the group’s leader, Hassan Nasrallah. That attack was a reprisal for a rocket attack from Lebanon that killed 12 children in the Israeli-controlled Golan Heights.

Last Friday, Israeli forces flattened a residential building in an airstrike targeting Ibrahim Aqeel, another top Hezbollah leader, alongside several other leaders of the group’s commando unit. At least 55 people were killed in the strike, including several children and other noncombatants.

And on Monday, Israel tried to assassinate a third member of the Jihad Council, Ali Karaki, with an airstrike in Beirut. Hezbollah has denied that Mr. Karaki was killed and has said he had been taken to a “safe place” in the wake of the strike.

While Israel has long been a target of criticism in the United Nations General Assembly, the war with Hamas in Gaza, as well as Israel’s sharply intensified attacks on Hezbollah in Lebanon, have ratcheted up the sweep of denunciations by numerous world leaders. Some also condemned the Hamas-led Oct. 7 attack on Israel that killed more than 1,200 people.

Without naming the United States specifically, Mr. Erdogan lambasted those countries that have called for a cease-fire while continuing to deliver weapons to Israel. He said that the need to confront the government of Prime Minister Benjamin Netanyahu of Israel was as imperative as the World War II effort to confront Hitler. And he hailed university students and other protesters around the world for their stand against the war in Gaza.

Danny Danon, the Israeli ambassador to the United Nations, responded in a statement, saying that while terrorists in both Gaza and Lebanon were attacking Israel, “There is Erdogan who comes every year to the U.N. and spreads pure hatred against the state of Israel.” Mr. Netanyahu is expected to address the General Assembly on Thursday, a trip he delayed earlier this week amid the expanded assault on Hezbollah.

The leaders who spoke critically of Israel all referred to the staggering death toll in Gaza — more than 41,000, according to the local health authorities — as they sought to illustrate the war’s devastation.

“This Israeli government has killed more children, more journalists, more aid workers, and more medical personnel than any other war in recent memory,” said King Abdullah II of Jordan, expressing anger and frustration over the Israeli attacks on Gaza and parallel deadly clashes in the Israeli-occupied West Bank.

In one of the few concrete proposals for addressing at least part of the crisis, Abdullah called for the United Nations to enforce a “Gaza humanitarian gateway” to deliver food, water, medicine and other desperately needed supplies.

He and other speakers suggested that Israel was not interested in achieving peace with the Arab world. “Consecutive Israeli governments, emboldened by years of impunity, have rejected peace and chosen confrontation instead,” he said.

Sheikh Tamim bin Hamad Al Thani, the emir of Qatar, whose mediators were instrumental in negotiating a temporary cease-fire and an exchange of prisoners for hostages late last year, also suggested that Israel was not a sincere partner in later peace talks that are now at a stalemate.

“A whole society is destroyed in the course of the genocide against segments of the Palestinian people,” he said.

Israel has maintained that it is Hamas that is not bargaining in good faith.

Mr. Al Thani also said that the booby-trapped pagers and walkie-talkies that killed hundreds of people and injured thousands more in Lebanon last week were a “major crime.” Current and former defense officials have attributed the blasts to an Israeli operation against Hezbollah. Israel has not claimed responsibility for the attacks.

President Cyril Ramaphosa of South Africa stressed that his country’s case before the International Court of Justice accusing Israel of committing genocide in Gaza was connected to his own country’s experience.

“The violence the Palestinian people are being subjected to is a grim continuation of more than half a century of apartheid that has been perpetrated against Palestinians by Israel,” Mr. Ramaphosa said. “We South Africans know what apartheid looks like. We lived through apartheid. We suffered and died under apartheid. We will not remain silent and watch as apartheid is perpetrated against others.”

Many of the leaders accused the United Nations of failing in its moral obligation to bring about a cease-fire in Gaza.

“It’s no surprise that both inside and outside this hall, trust in the U.N.’s cornerstone principles and ideals is crumbling,” said King Abdullah.

Farnaz Fassihi, Safak Timur and Anushka Patil contributed reporting.

At this year’s General Assembly, Mr. Netanyahu’s moment on the world stage will be clouded by the conflict and the backdrop of global condemnation for his prosecution of the war in Gaza. More than 41,000 people have been killed in Gaza, according to local health authorities, who do not distinguish between civilians and combatants. And more than 600 Palestinians have been killed over the same period in the occupied West Bank, mostly in military actions and a few at the hands of extremist Jewish settlers, according to the United Nations.

Israel is battling a genocide case at the U.N.’s top court over the Gaza war while the chief prosecutor of the International Criminal Court has requested arrest warrants for Mr. Netanyahu and his defense minister, Yoav Gallant, along with several Hamas leaders, on accusations of crimes against humanity.

And in just days of intense Israeli assaults on southern and eastern Lebanon, hundreds of people have been reported dead and thousands wounded. With that escalation still underway, Mr. Netanyahu has delayed his arrival in New York by days, and his speech appears to have been brought forward from Friday to Thursday, to shorten his time abroad.

For Mr. Netanyahu, the assembly presents an opportunity to make Israel’s case. As Israel’s longest serving prime minister — his first term in office was in the 1990s, though he has been in and out of power since — he ranks as one of the assembly’s most veteran leaders.

“He’s the figure most identified with Israel for the last generation,” said Mazal Mualem, an Israeli political commentator for Al-Monitor, a Middle East news site, and the author of a biography of the Israeli leader, “Cracking the Netanyahu Code.”

Mr. Netanyahu views such occasions as being of historic importance, Ms. Mualem added, though at times in the past, many in the U.N. chamber have left the General Assembly hall when he takes the microphone, leaving him to speak to a largely empty hall.

That might matter less to Mr. Netanyahu, who is known to tailor his speeches abroad toward impressing his audience back home, burnishing his domestic credentials as a world player leagues above his competitors.

“His target audience will clearly be his home audience,” Ms. Mualem said.

His domestic audience is hardly united over his leadership. Many Israelis had demanded his resignation in the immediate aftermath of the Hamas-led assault, which caught Israel off-guard and exposed years of deep intelligence, military and policy failures, mostly on Mr. Netanyahu’s watch. Yet he has so far staved off internal and external pressures, and has chalked up a personal victory for now, at least, by surviving politically, against the odds.

“He’s come after the worst year in Israel’s history and his own history, and he just doesn’t give up,” said Mitchell Barak, an Israeli pollster and analyst who worked as an aide to Mr. Netanyahu in the 1990s.

“Bibi is the Israeli entrepreneur who doesn’t let failure stand in his way,” he said, referring to Mr. Netanyahu by his popular nickname. “He keeps moving forward.”

War death tolls are estimates, and exact comparisons between conflicts are difficult. But the toll on Monday in Lebanon exceeded most daily tolls in Gaza over the past year and more than doubled the average daily death rate during the deadliest year of the Syrian civil war.

Here’s what else to know.

The number of targets struck by Israel

The Israeli military said it hit more than 1,600 targets in Lebanon on Monday, a number that has few, if any, precedents in 21st-century warfare, according to Emily Tripp, the director of Airwars, a British conflict monitor.

It is roughly 300 more than the number of targets Israel struck during the opening three days of its Gaza offensive after the Hamas-led attack on Oct. 7 — a number that itself was considered unusually high.

During the U.S.-led air campaign against the Islamic State in Iraq and Syria between 2014 and 2017, Western fighter jets struck an average of 650 targets a month across a much wider area, according to data published by the Department of Defense.

“Prior to the Gaza war, munitions deployed with this intensity and with this frequency would have been almost unheard-of,” Ms. Tripp said. “There is no comparison in terms of death toll or munitions use with previous 21st-century air campaigns of this nature, as far as we know.”

The Israeli military said Hezbollah fired 250 rockets toward Israel on Monday, most of which were intercepted by Israeli air-defense missiles or missed their targets. At least one man was reported to have been wounded by shrapnel. Since October, Hezbollah has fired more than 8,000 missiles toward Israeli positions, according to the Israeli military.

How the Lebanese death toll compares

The Lebanese health minister, Dr. Firass Abiad, said 558 people were killed on Monday in Israeli strikes — an unusually high number by the standards of contemporary war, experts said.

In Gaza last October, it took 18 days for the reported daily death toll to exceed 500. The Monday toll is about half the entire casualty count during the monthlong Israel-Hezbollah war of 2006. And it is far higher than the average daily toll during the Syrian war in 2014, the deadliest year of that decade-long conflict.

How the Lebanese government collates the death toll

Lebanon’s health ministry runs an emergency operations center that collects casualty numbers from private and state-run hospitals, collating them to create a national toll from the war, according to health officials.

These figures have historically been viewed as reliable and are cited regularly by the United Nations, which helped the ministry develop the operations center.

Hezbollah, the powerful Shiite militia backed by Iran, does not run the ministry. It is overseen by the government of Lebanon, whose members are split along sectarian and political lines.

Dr. Abiad, a former board chairman at Lebanon’s largest hospital, is generally considered apolitical and won praise and prominence for his data-driven assessments during the coronavirus pandemic. He was first proposed for the role of health minister by Saad Hariri, a Sunni former prime minister who is not allied with Hezbollah, and was formally appointed by Mr. Hariri’s successor.

The ratio of slain combatants to civilians

The Lebanese health ministry does not provide detailed breakdowns of the numbers of civilians and combatants killed. But Dr. Abiad said in a brief phone interview on Tuesday that the “overwhelming majority, if not all,” of those killed and injured on Monday were civilians.

For his statement to be true, the number of civilian men killed in Lebanon on Monday would need to overwhelmingly exceed the combined number of slain women and children. The Lebanese health ministry said that 94 women and 50 children were killed on Monday, or just over 25 percent of the total death toll, but it did not specify the number of slain male civilians.

The Israeli military has said it was targeting military operatives, weapons caches and rocket launchers, many of them hidden in civilian neighborhoods and homes.

Ms. Tripp said the number of slain women and children was “consistent with what we’ve seen in conflicts such as Iraq, but lower compared to the recent Gaza war.”

In Gaza, more than 54 percent of the roughly 34,000 people recently named as victims by the Gaza health authorities were said to be either women or boys and girls under 18. Roughly 7,000 other victims are still to be identified by the health authorities, according to the ministry’s chief statistician.

Lauren Leatherby contributed reporting.

But months of talks have failed to yield an end to the conflict, which began on Oct. 7, when Hamas led a deadly attack on Israel. In the latest negotiations toward a truce, international mediators have aimed to narrow the gaps between Israel and the Iran-backed militant group. But Hamas has demanded that Israel fully withdraw from Gaza, and Prime Minister Benjamin Netanyahu of Israel has insisted that he will not give up control of the enclave’s border with Egypt.

The prospects of ending the war in Gaza appear more bleak amid a significant escalation in recent days of a conflict between Israel and the Lebanese militant group Hezbollah, an ally of Hamas. Hezbollah and Israel have been exchanging cross-border missile and drone attacks since October, killing hundreds of Lebanese and forcing the evacuations of tens of thousands of civilians on both sides of the border.

Mr. Biden, who delivered a wide-ranging speech to the U.N. General Assembly that included passages about the war in Ukraine, as well as artificial intelligence, also called for a two-state solution to the Israeli-Palestinian conflict involving the creation of a Palestinian state.

It is a long-term goal of U.S. policymakers and an objective of Palestinian leaders, but decades of efforts have yet to achieve it. Mr. Netanyahu has resisted U.S. pressure over the issue, particularly after Oct. 7. He has argued that Israel’s safety requires controlling security in the Israeli-occupied West Bank and has said this it is incompatible with a Palestinian state.

Mr. Biden also called for the return of hostages seized on Oct. 7. Around 1,200 people were killed in the attack, and more than 250 others were taken hostage. Over 100 of those were released during a weeklong cease-fire that began in November, and Israel has freed several others during military operations. But dozens more remain in captivity, and Hamas is holding the bodies of hostages who have died or have been killed since the initial attack.

“The world must not flinch from the horrors of Oct. 7,” Mr. Biden said.

The United States has supplied Israel with military and diplomatic support since the war began, and some of the president’s critics have accused him of paying insufficient attention to civilian suffering in Gaza.

More than 40,000 people have died in the enclave, the bulk of them children, women and older people, according to Gaza’s health ministry. At the same time, the enclave has been devastated by Israeli airstrikes and fighting, and almost all of the population has been forced to flee their homes.

“Innocent civilians in Gaza are also going through hell,” Mr. Biden said. “They didn’t ask for this war that Hamas started.”

After nearly a year, roughly 100 of the more than 250 hostages held by Hamas since their Oct. 7 attacks remain in the clutches of Palestinian militants in Gaza. They include women and older people kidnapped from their homes, as well as soldiers abducted from military bases.

Israel and Hamas are deadlocked in negotiations over conditions for a truce that would free them. The Israeli authorities have declared that more than 30 hostages are already presumed dead, and their families fear that number will only rise as their loved ones languish in captivity.

With all eyes on Israel’s escalating battle with Hezbollah in Lebanon, many families now fear any hopes to save the hostages are rapidly vanishing, said Itzik Horn, whose sons Eitan, 38, and Iair, 46, are still held.

“We’ve been abandoned again and again” by the Israeli government, said Mr. Horn. “And now, the resources and attention are heading to the north.”

Both Eitan and Iair were abducted from Nir Oz, a border village that was devastated by the Hamas-led attack. Many of its roughly 400 members were either killed or kidnapped by Palestinian militants.

Eitan was visiting his brother, who held various roles in Nir Oz, including running the local pub, when the attack began. Soon afterward, Itzik, their father, lost contact with them. In November, a weeklong truce with Hamas secured the release of 105 hostages, some of whom attested to having seen the two brothers in the tunnels, said Mr. Horn.

Noam Dan, a relative of Ofer Kalderon — who was also abducted from Nir Oz — accused Benjamin Netanyahu, the Israeli prime minister, of “cruelly neglecting” the remaining hostages in favor of the escalation. Mr. Kalderon’s children, Sahar and Erez, were released in the weeklong truce with Hamas in November.

Mr. Netanyahu has said that he is committed to securing the release of the remaining hostages. But he has repeatedly said he will not agree to a cease-fire with Hamas that compromises on what he called Israel’s fundamental security needs.

Like many close to the remaining captives, Ms. Dan said she believed Mr. Netanyahu was more worried about the future of his government than securing the release of the hostages. Some of his coalition partners have opposed recent cease-fire proposals.

“What matters to him most is his political survival, and now he’s managed to redirect the conversation close to the anniversary of his resounding failure,” she said. Ms. Dan and others blame Mr. Netanyahu’s government for failing to prevent Hamas’s surprise assault on Israel last year.

Gazans similarly fear that their plight will be shoved aside as the conflict there nears a once-unthinkable milestone: a year of almost constant war. Hundreds of thousands have crowded into an Israeli-designated “humanitarian zone” in central and southern Gaza, often living in rudimentary tent encampments where finding enough food and water can be a daily struggle.

Hundreds of thousands of Israelis have participated in demonstrations calling on the Israeli government to reach an agreement with Hamas to free the captives. The discovery of the six hostages dead in a tunnel a little over three weeks ago — executed by their Hamas guards, according to Israel — shocked the country and prompted mass protests.

But the negotiations stalled, primarily over Mr. Netanyahu’s demand to retain an Israeli military presence along Gaza’s border with Egypt. Hamas immediately rejected the condition.

In Israel, television panels full of former generals and political analysts pick apart the latest reports of strikes and counter-strikes over Israel’s northern border with Lebanon. Correspondents report from northern Israeli communities under rocket fire.

“There’s no momentum, no negotiations, not even a bit of anything. Everyone’s now busy with war in the north,” Mr. Horn said.

Monday was also the deadliest day in Lebanon since a 15-year civil war that ended in 1990.

The figures released by Lebanon’s health ministry do not distinguish between civilians and combatants. Mr. Abiad said the “overwhelming majority” killed yesterday were unarmed, and that dozens of women and children were among the dead.

Violence between Israel and Hezbollah, the Iranian-backed Lebanese militia, has escalated over the last week as the two groups ramp up tit-for-tat strikes across the Lebanese border.

Hezbollah’s leaders have vowed to retaliate against Israeli strikes, saying the group will continue its attacks on Israel until a cease-fire deal is reached between Israel and Hamas, Hezbollah’s ally.

More than 40,000 people have been killed in Gaza during the first 11 months of the war, according to the Gazan Health Ministry, which does not distinguish between civilians and combatants. Many more have been displaced. Lebanon had remained relatively unscathed until recently, when Israel turned its attention to Hezbollah.

Israel pummeled Lebanon with airstrikes on Monday, the deadliest day in the country since at least 2006. The attack left more than 550 dead and more than 1,500 injured. The Israeli military said in a statement on Tuesday that its air force hit about 1,600 Hezbollah targets in Lebanon on Monday and was continuing to strike the country.

Israel’s escalation comes after hundreds of pagers and walkie-talkies owned by Hezbollah members exploded across Lebanon last week, killing more than 30 people, including two children, and injuring thousands. Israel did not explicitly claim responsibility, but Yoav Gallant, the Israeli defense minister, said that the “center of gravity” of Israel’s military effort, which had concentrated on eliminating Hamas in Gaza, was “moving north.”

Israel bombarded Lebanon throughout the weekend. On Friday, Israel hit Beirut, the Lebanese capital, killing several top Hezbollah commanders, including one of the group’s most senior leaders, according to Israeli officials. The attack also flattened a residential building, killing and wounding dozens of civilians.

On Sunday, Hezbollah launched more than 100 missiles, rockets and drones into Israel, striking around 30 miles inside the country’s borders in its deepest attack since last October.

António Guterres, the U.N. secretary-general, called on Monday for an immediate end to hostilities between Israel and Hezbollah, with his spokesman, Stéphane Dujarric, saying in a statement that, “there is no military solution that will make either side safer.”

On Tuesday, Danny Danon, Israel’s ambassador to the U.N., said Israel was not eager to start a ground invasion in Lebanon. “We don’t want to send our boys to fight in a foreign country. But we are determined to protect the civilians of Israel. We prefer a diplomatic solution — if it’s not working, we are using other methods to show to the other side that we mean business.”

Israel said it had hit more than 1,000 sites, mostly in southern and eastern Lebanon, aimed at the fighters and military infrastructure of Hezbollah, the Lebanese political party and militia it has been fighting along the Israel-Lebanon border for 11 months. At least 558 people were killed in the strikes, including 94 women and 50 children, Lebanon’s health minister told reporters on Tuesday.

That toll marked a terrible milestone for Lebanon: Monday was the country’s deadliest day since its 15-year civil war, which ended in 1990.

“The victims of a strike by the Israeli enemy on the village of Arnoun. Targeted in their homes!” read text over a photo shared on social media of three women killed in one of the strikes.

The death toll given by the health ministry did not differentiate between fighters and civilians, and the strikes overwhelmingly hit parts of the country where Hezbollah dominates, suggesting that Israel had struck another fierce blow to the group. That capped a week in which Israel also blew up electronic devices distributed by Hezbollah, killing dozens of people and injuring thousands more, and assassinated a group of its military leaders in an airstrike near Beirut.

Some experts on Hezbollah suggested that Israel’s recent attacks had largely debilitated the group, leaving its membership in disarray.

“They have no options,” said Hilal Khashan, a professor of political science at the American University of Beirut and the author of a book on Hezbollah. “Israel disabled Hezbollah.”

The attacks since last Tuesday have hit both Hezbollah’s leadership and its fighters hard while severely disrupting their ability to communicate and coordinate large-scale retaliation against Israel, he said.

“Now Hezbollah is headless,” Mr. Khashan said. “Israel eliminated Hezbollah’s leadership, so the rank and file are astray.”

Other experts acknowledged the severity of the blows but were more cautious about writing the group off so quickly, citing its large weapons stockpiles and history of adapting to confront Israel’s much more high-tech military.

Hezbollah was formed with Iranian help in the 1980s to fight the Israeli occupation of southern Lebanon, which ended in 2000. In the years since, it has grown into a significant political player in Lebanon and the country’s most powerful military force while sending fighters to help other Iranian-backed forces in Syria, Iraq and Yemen. Israel, the United States and other countries consider it a terrorist organization.

Hezbollah launched cross-border attacks on Israel after the start of the war in Gaza last October in solidarity with the Palestinian group Hamas, which is also backed by Iran. Israel responded by striking Hezbollah sites in Lebanon, but for many months, both sides made efforts to keep their battle focused on the border area. Hezbollah’s leader, Hassan Nasrallah, has said that the group would continue striking Israel as long as the war in Gaza continued.

Last week, Israeli leaders sharply escalated the attacks on the group, saying that removing it from the border zone was the only way that the tens of thousands of Israelis who have fled their homes in the area could return home. (About 90,000 Lebanese have fled their homes near the border, too.)

A diplomat with knowledge of the talks aimed at containing the violence, who spoke on condition of anonymity because they were not authorized to brief the news media, said Israel was demanding that Hezbollah agree to a cease-fire along the Lebanon-Israel border regardless of what happens in the war in Gaza and that it must move its forces and arms away from the frontier.

Joseph Daher, who teaches at Lausanne University in Switzerland and wrote a book about Hezbollah, said Israel had greatly increased the pressure but that Hezbollah was unlikely to agree to its demands.

“It puts pressure politically and socially on Hezbollah, but will it make Hezbollah separate the Gaza front from the Lebanese front? I don’t think so,” he said. “Nor will it get Hezbollah to withdraw its military capacities from the border area.”

So far, at least, Hezbollah does not appear to have changed its strategy of trying to avoid a total war that could cause deep damage to the movement and to Lebanon, Mr. Daher said.

“We are already in a form of war, but they don’t want a total war with Israel,” he said. “This is why they are maintaining a calculated and to some extent moderated reaction, although intensifying their attacks against Israel, as seen this weekend.”

Hezbollah has continued to strike Israel in recent days, including with long-range missiles that it says it has aimed at military bases and other sensitive sites. Many have been intercepted by Israel’s defenses and little serious damage has been reported.

Before the Gaza war, Hezbollah was widely considered one of the most heavily armed nongovernmental forces in the world.

Its military wing was believed to have between 20,000 and 30,000 members, including low-level guerrillas, experienced commanders and teams of technicians focused on rockets, missiles and drones, according to Philip Smyth, an analyst with the Atlantic Council’s counterterrorism project.

Its arsenal included more than 100,000 rockets and missiles, likely including intermediate-range ballistic missiles, cruise missiles and portable antiaircraft weapons. Its fighters have deployed anti-tank missiles to blow up Israeli vehicles, and Israeli officials have said it has developed precision-guided missiles that could hit military bases or critical infrastructure.

Some of Hezbollah’s senior leaders have been with the group for decades, and many of its fighters got battlefield experience during the Syrian civil war and in the fight against the Islamic State in Syria and Iraq.

How much of Hezbollah’s force and fighting ability remains after 11 months of war — and after the last week’s attacks — is an open question. The group had announced the deaths of more than 400 fighters between October and the most recent attacks.

Israel’s recent escalation injured many midlevel figures and killed military planners and a still unknown number of fighters and other operatives. Still, it has not yet prompted a large retaliation from Hezbollah, either because the group has chosen not to mount one or because it simply cannot.

In either case, Israel has robbed Hezbollah of its aura of power and competence, especially by turning its own covert communications network into a weapon against it, Mr. Smyth said.

“I don’t think anyone is under any illusions that this was a very deep attack that penetrated an opaque organization that prides itself on being opaque,” he said.

Mr. Pezeshkian’s speech was unusually reconciliatory in tone and words. In the past, Iranian presidents have used the global platform of the Assembly to project defiance, and have threatened to take revenge on American presidents and denied the Holocaust in their speeches.

Instead, Mr. Pezeshkian extended an olive branch to Iran’s Western adversaries, with the exception of Israel. To what extent his rhetoric will match Iran’s actions remains to be seen.

The Iranian president praised Iran’s nuclear deal with the West as a diplomatic achievement and said Tehran was ready to engage in negotiations with all sides to return to the deal and lift U.S. sanctions.

He said once that hurdle is overcome, “fully and in good faith, dialogue on other issues can follow.”

Still, analysts said that Mr. Pezeshkian’s peace message did not match the country’s actions on the ground, where the powerful Revolutionary Guards Corps supports and arms militant groups like Hamas in Gaza, Hezbollah in Lebanon, the Houthis in Yemen and militias in Iraq and Syria. These groups have been launching attacks on Israel, U.S. military bases and, in the case of the Houthis, ships on the Red Sea.

On Oct. 7, Hamas invaded Israel from Gaza, killing roughly 1,200 people, including women and children, according to Israeli authorities, and taking more than 200 hostages.

Iran has denied that it supports Russia in its war against Ukraine. But Western officials say that the country has been supplying Russia with drones, which the Kremlin has used against targets in Ukraine for more than a year, and that Iran recently delivered short-range ballistic missiles to Russia.

When it came to Israel, Mr. Pezeshkian took a harsher stand but stopped short of directly threatening the country.

Like many world leaders who spoke at the Assembly today, Mr. Pezeshkian slammed Israel for what he called “atrocities in Gaza,” the wave of recent attacks in Lebanon that have killed hundreds of people and a covert war with Iran assassinating its nuclear scientists, diplomats and “guests on our soil” — a reference to the killing of Hamas’s leader, Ismail Haniyeh, in Tehran.

Mr. Pezeshkian defended Iran’s support of the militant networks known as the “axis of resistance” in the Middle East which have taken up arms against Israel, including Hamas in Gaza and Hezbollah in Lebanon. He called the networks “popular liberation movements of people that have been victims of four generations of the crimes and colonialism of the Israeli regime.”

Mr. Pezeshkian, a heart surgeon, is a reformist who won the election in July against a conservative candidate. Iran’s supreme leader, Ayatollah Ali Khamenei, who has the last word on all state matters, has endorsed Mr. Pezeshkian and called on all government branches and political factions to cooperate with him.

“He has a really difficult balancing act to put on display in New York, because a lot of the priorities he is pursuing are mutually exclusive,” Ali Vaez, the Iran director for the International Crisis Group, said of Mr. Pezeshkian. “He wants to improve relations with the West when Iran is on the opposite side of the West in the wars in Gaza and Ukraine.”

Mr. Pezeshkian called on the international community to immediately bring a cease-fire in Gaza and “bring an end to the desperate barbarism of Israel in Lebanon, before it engulfs the region and the world,” saying that aggression with thousands of victims “cannot go unanswered.”

In April, after Israel struck Iran’s Embassy in Damascus, Syria, Iran retaliated by launching hundreds of drones and missiles against Israel. And Tehran vowed revenge after Israel assassinated Hamas’s political leader, Mr. Haniyeh, but after intense diplomatic efforts military commanders said Iran would retaliate at a time and place of its choosing.

Mr. Pezeshkian said he had a message for the American people: “We have the opportunity to transcend these limitations and enter a new era. This era will commence with the acknowledgment of Iran’s security concerns and cooperation on mutual challenges.”

Mr. Zelensky was speaking ahead of meetings this week, during which he plans to present his “victory plan” to President Biden and other U.S. officials. So far, he has withheld details of the plan from the public. Mr. Zelensky has also called for the United States and other allies to permit Ukraine to use long-range missiles provided by the West to strike deep into Russia.

Secretary General António Guterres briefed the Council, telling diplomats that it was past time to end the war in Ukraine, which has led to catastrophic civilian suffering and spillover consequences, such as a rise in grain and energy prices and the displacement of millions. He also laid out the U.N.’s role in providing lifesaving humanitarian aid to some 6.2 million people in Ukraine this year, and he appealed to donors for more funding.

With the bitter winter approaching, only half of the U.N.’s response plan was funded, Mr. Guterres pointed out.

“The longer this tragic war continues, the greater the risk of escalation and spillover,” he said.

Antony J. Blinken, the U.S. secretary of state, said the Security Council must act to address North Korea and Iran sending weapons to Russia for its war. He repeated an assertion that he first made during a trip to Britain this month — that in exchange for Iran equipping the Russian military with armed drones and short-range ballistic missiles, Russia was “sharing technology with Iran on nuclear issues, as well as space information.”

Mr. Blinken did not give more details. Russia was one of several powerful nations that joined an agreement led by President Barack Obama to place limits on Iran’s nuclear program.

Mr. Blinken said the Security Council must also help Ukraine reach “a just and lasting peace.” That means any diplomatic settlement must allow Ukraine to retain its full sovereignty and territorial integrity, despite the intent of President Vladimir V. Putin of Russia to occupy and annex large parts of eastern Ukraine, in addition to Crimea.

The Security Council has been deadlocked over the war in Ukraine since the start of the Russian invasion. Russia, a permanent member of the Council with veto power, has blocked resolutions calling for an immediate withdrawal of its troops.

While Israel has long been a target of criticism in the United Nations General Assembly, the war with Hamas in Gaza, as well as Israel’s sharply intensified attacks on Hezbollah in Lebanon, have ratcheted up the sweep of denunciations by numerous world leaders. Some also condemned the Hamas-led Oct. 7 attack on Israel that killed more than 1,200 people.

Without naming the United States specifically, Mr. Erdogan lambasted those countries that have called for a cease-fire while continuing to deliver weapons to Israel. He said that the need to confront the government of Prime Minister Benjamin Netanyahu of Israel was as imperative as the World War II effort to confront Hitler. And he hailed university students and other protesters around the world for their stand against the war in Gaza.

Danny Danon, the Israeli ambassador to the United Nations, responded in a statement, saying that while terrorists in both Gaza and Lebanon were attacking Israel, “There is Erdogan who comes every year to the U.N. and spreads pure hatred against the state of Israel.” Mr. Netanyahu is expected to address the General Assembly on Thursday, a trip he delayed earlier this week amid the expanded assault on Hezbollah.

The leaders who spoke critically of Israel all referred to the staggering death toll in Gaza — more than 41,000, according to the local health authorities — as they sought to illustrate the war’s devastation.

“This Israeli government has killed more children, more journalists, more aid workers, and more medical personnel than any other war in recent memory,” said King Abdullah II of Jordan, expressing anger and frustration over the Israeli attacks on Gaza and parallel deadly clashes in the Israeli-occupied West Bank.

In one of the few concrete proposals for addressing at least part of the crisis, Abdullah called for the United Nations to enforce a “Gaza humanitarian gateway” to deliver food, water, medicine and other desperately needed supplies.

He and other speakers suggested that Israel was not interested in achieving peace with the Arab world. “Consecutive Israeli governments, emboldened by years of impunity, have rejected peace and chosen confrontation instead,” he said.

Sheikh Tamim bin Hamad Al Thani, the emir of Qatar, whose mediators were instrumental in negotiating a temporary cease-fire and an exchange of prisoners for hostages late last year, also suggested that Israel was not a sincere partner in later peace talks that are now at a stalemate.

“A whole society is destroyed in the course of the genocide against segments of the Palestinian people,” he said.

Israel has maintained that it is Hamas that is not bargaining in good faith.

Mr. Al Thani also said that the booby-trapped pagers and walkie-talkies that killed hundreds of people and injured thousands more in Lebanon last week were a “major crime.” Current and former defense officials have attributed the blasts to an Israeli operation against Hezbollah. Israel has not claimed responsibility for the attacks.

President Cyril Ramaphosa of South Africa stressed that his country’s case before the International Court of Justice accusing Israel of committing genocide in Gaza was connected to his own country’s experience.

“The violence the Palestinian people are being subjected to is a grim continuation of more than half a century of apartheid that has been perpetrated against Palestinians by Israel,” Mr. Ramaphosa said. “We South Africans know what apartheid looks like. We lived through apartheid. We suffered and died under apartheid. We will not remain silent and watch as apartheid is perpetrated against others.”

Many of the leaders accused the United Nations of failing in its moral obligation to bring about a cease-fire in Gaza.

“It’s no surprise that both inside and outside this hall, trust in the U.N.’s cornerstone principles and ideals is crumbling,” said King Abdullah.

Farnaz Fassihi, Safak Timur and Anushka Patil contributed reporting.

So he decided not to go.

“I made this decision, because there is confusion that has arisen between the United Nations, the State Department and the representation of Haiti to the United Nations,” Mr. Leblanc told reporters at a news conference Saturday.

Haiti’s last elected president, Jovenel Moïse, was assassinated three years ago. For now, the country is governed by the presidential council, whose members will rotate the presidency until elections are held in 2026 to choose an actual president. Because he has not been elected, Mr. Leblanc is essentially the acting president.

Haiti has no shortage of representatives at the United Nations.

The prime minister, Garry Conille, is already in New York receiving diplomatic security. Another transitional council member, Leslie Voltaire, also flew to New York and met with U.N. Secretary General António Guterres on Sunday. He is also getting protection while in New York, according to the Secret Service.

The decision to cut Mr. Leblanc out was widely viewed as an embarrassing blow to him and the council — and another chapter in Haiti’s long history of political upheaval.

But a day after Mr. Leblanc’s announcement, the Biden administration backtracked.

“President Leblanc will receive a full protective detail, as provided to every Head of State,” the embassy said on X. “The U.S. government takes the security of foreign dignitaries in the United States very seriously and regrets delays in approving his security detail due to the complexity of our internal processes.”

A U.S. government official who was not authorized to speak openly on the matter because of the diplomatic sensitivities said the dust-up had been the result of a translation mistake.

The title of transitional council president had been translated as coordinator, which bumped Mr. Leblanc down to a cabinet-level official — someone who would not be entitled to a full security detail provided to heads of state, the person said.

His security restored, Mr. Leblanc said he would go to New York after all, and deliver Haiti’s address to the assembly on Thursday.

At this year’s General Assembly, Mr. Netanyahu’s moment on the world stage will be clouded by the conflict and the backdrop of global condemnation for his prosecution of the war in Gaza. More than 41,000 people have been killed in Gaza, according to local health authorities, who do not distinguish between civilians and combatants. And more than 600 Palestinians have been killed over the same period in the occupied West Bank, mostly in military actions and a few at the hands of extremist Jewish settlers, according to the United Nations.

Israel is battling a genocide case at the U.N.’s top court over the Gaza war while the chief prosecutor of the International Criminal Court has requested arrest warrants for Mr. Netanyahu and his defense minister, Yoav Gallant, along with several Hamas leaders, on accusations of crimes against humanity.

And in just days of intense Israeli assaults on southern and eastern Lebanon, hundreds of people have been reported dead and thousands wounded. With that escalation still underway, Mr. Netanyahu has delayed his arrival in New York by days, and his speech appears to have been brought forward from Friday to Thursday, to shorten his time abroad.

For Mr. Netanyahu, the assembly presents an opportunity to make Israel’s case. As Israel’s longest serving prime minister — his first term in office was in the 1990s, though he has been in and out of power since — he ranks as one of the assembly’s most veteran leaders.

“He’s the figure most identified with Israel for the last generation,” said Mazal Mualem, an Israeli political commentator for Al-Monitor, a Middle East news site, and the author of a biography of the Israeli leader, “Cracking the Netanyahu Code.”

Mr. Netanyahu views such occasions as being of historic importance, Ms. Mualem added, though at times in the past, many in the U.N. chamber have left the General Assembly hall when he takes the microphone, leaving him to speak to a largely empty hall.

That might matter less to Mr. Netanyahu, who is known to tailor his speeches abroad toward impressing his audience back home, burnishing his domestic credentials as a world player leagues above his competitors.

“His target audience will clearly be his home audience,” Ms. Mualem said.

His domestic audience is hardly united over his leadership. Many Israelis had demanded his resignation in the immediate aftermath of the Hamas-led assault, which caught Israel off-guard and exposed years of deep intelligence, military and policy failures, mostly on Mr. Netanyahu’s watch. Yet he has so far staved off internal and external pressures, and has chalked up a personal victory for now, at least, by surviving politically, against the odds.

“He’s come after the worst year in Israel’s history and his own history, and he just doesn’t give up,” said Mitchell Barak, an Israeli pollster and analyst who worked as an aide to Mr. Netanyahu in the 1990s.

“Bibi is the Israeli entrepreneur who doesn’t let failure stand in his way,” he said, referring to Mr. Netanyahu by his popular nickname. “He keeps moving forward.”

He said Iran was not seeking war. “Iran is seeking a strong, stable and unified region,” Mr. Pezeshkian said.

He also denied that Iran was supporting Russia in its war against Ukraine. But Western officials say that Iran has been supplying Russia with drones, which Russia has used against targets in Ukraine, for more than a year, and that it recently delivered short-range ballistic missiles to Russia.

When it came to Israel, Mr. Pezeshkian said on Monday that no global pact could guarantee stability and peace as long as Israel had impunity for its military conduct in the war against Hamas in Gaza, which he called “genocide” and “blind state-sponsored terrorism.” Gazan health officials say the war has killed more than 40,000 Palestinians, many of them women and children. The Hamas-led attack on Israel on Oct. 7 killed about 1,200 and led to the abduction of 250 others to Gaza.

Analysts said that Mr. Pezeshkian’s peace message did not match Iran’s actions on the ground, where the country’s powerful Revolutionary Guards Corps supports and arms militant groups like Hezbollah in Lebanon, the Houthis in Yemen and militias in Iraq and Syria. These groups have been launching attacks on Israel, United States military bases and, in the case of Houthis, ships in the Red Sea.

Mr. Pezeshkian, a heart surgeon, is a reformist who won the election in July against a conservative candidate. Iran’s supreme leader, Ayatollah Ali Khamenei, who has the last word on all state matters, has endorsed Mr. Pezeshkian and called on all government branches and political factions to cooperate with him.

“He has a really difficult balancing act to put on display in New York, because a lot of the priorities he is pursuing are mutually exclusive,” Ali Vaez, the Iran director for the International Crisis Group, said of Mr. Pezeshkian. “He wants to improve relations with the West when Iran is on the opposite side of the West in the wars in Gaza and Ukraine.”

In recent days, Israel and Hezbollah, the Lebanese militant group allied with Iran, have intensified cross-border attacks against each other, raising fears of an all-out war. Tensions have also flared between Iran and Israel, with the two coming to the brink of war twice this year.

In April, after Israel struck Iran’s Embassy in Damascus, Syria, Iran retaliated by launching hundreds of drones and missiles against Israel. And Tehran vowed revenge after Israel assassinated Hamas’s political leader, Ismail Haniyeh, in Tehran in July.

The Iranian president arrived in New York with a team of seasoned diplomats who were part of Iran’s nuclear negotiating team. His delegation included Iran’s foreign minister, Abbas Araghchi; and the former Foreign Minister Mohammad Javad Zarif, who now serves as vice president of strategy.

Mr. Pezeshkian has expressed openness to reopening nuclear negotiations with the West, with the aim of lifting American economic sanctions imposed by President Donald J. Trump after he unilaterally exited the nuclear deal between Iran and world powers in 2018. Mr. Araghchi said on Instagram that he planned to stay in New York for an extra few days to meet other foreign ministers with the aim of restarting talks.

Amid the diplomatic moves, the imprisoned human rights activist Narges Mohammadi, Iran’s Nobel Peace Prize laureate, appealed to world leaders to keep the country’s human rights violations and the quest for democracy and peace in the Middle East at the forefront.

“I implore you to include human rights in your discussions as a precondition to negotiations at any level in action and not just words,” Ms. Mohammadi said in a statement shared by her family.

Mr. Zelensky said he would make his case this week in meetings with President Biden and in a separate meeting with Keir Starmer, the prime minister of Britain, and Emmanuel Macron, the president of France.

“Our decision depends on their will,” he said in an interview with The New York Times on Tuesday morning at the United Nations with Mette Frederiksen, the prime minister of Denmark. “For today, they have to give, or say that they will not give.”

“Do they really want us to prevail, or is it about something long, some terrible and long tragedy?” Mr. Zelensky said.

Recent diplomatic discussions among the three allied nations have focused on the question of allowing Ukraine to use imported weapons for long-range fire into Russia. Mr. Starmer and Mr. Macron are leaning toward giving permission but want to coordinate with Mr. Biden, who could soon decide to support Britain and France in loosening their restrictions before the United States does anything similar, U.S. officials say.

Since Russia’s full-scale invasion of Ukraine in 2022, Mr. Biden has feared an escalation into a Russia-versus-NATO war and has only gradually given Ukraine certain weapons systems and slowly loosened some restrictions on their use.

Mr. Zelensky also said the allies should help Ukraine fully equip all its brigades. The country’s reserve units are underequipped and not properly trained on weapons systems provided by the United States and other allies, but that shortcoming can be addressed by the nations giving Ukraine enough arms quickly, he said.

Ms. Frederiksen said in the joint interview that the United States and Europe must prepare to support Ukraine in a war that could last for years longer, and that means loosening arms restrictions.

“I don’t think Ukraine can win with one arm on their back,” she told The Times. “So I think we need to end that discussion, to give what is needed, and actually to put it the other way around — ask Ukraine what is needed to win this war. And then we have to ensure that they will have what they need.”

Denmark, Sweden and Finland, all NATO members, have said Ukraine can do as it wishes with military aid from those countries. Mr. Zelensky and Ukrainian commanders say they want to use Storm Shadow missiles from Britain, as well as a similar missile supplied by France, to strike deep into Russia. In May, Mr. Biden agreed to let Ukraine use American weapons for short cross-border strikes against Russia but still banned long-range attacks.

Mr. Zelensky said on Tuesday that allies had given a lot in recent years, but never the full amount he has requested.

Both Mr. Zelensky and Ms. Frederiksen also said the United States and European nations needed to increase their capacity to produce weapons, and that allied investment in the production of arms inside Ukraine would help alleviate the shortage.

“We need to shift our mind-set,” Ms. Frederiksen said. “We still have a peacetime mind-set in the rest of Europe.”

“Of course we could have more production faster in the rest of Europe, if we took the right decisions, but at the same time helping inside Ukraine, I mean, co-production and so on,” she added, saying governments needed to encourage more direct investment in factories in Ukraine.

Mr. Zelensky noted that the European nations currently still produce more arms than Russia, and said, “What do we have to do to get it, just to get it to Ukraine?”

When asked about the “victory plan” that he has said he will present to Mr. Biden and other American politicians this week, Mr. Zelensky said a central component was bolstering Ukraine’s military — “real strengthening, not slow packages.”

Both Mr. Zelensky and Ms. Frederiksen also said NATO member nations must expedite Ukraine’s entry into the security organization.

Mr. Zelensky denounced the direct weapons aid that North Korea and Iran have given Russia, while Ms. Frederiksen said she believed China’s commercial partnerships with Russia had been pivotal in allowing Moscow to sustain its war effort. The Biden administration has said China helped Russia rebuild its defense industry despite U.S.- and Europe-led sanctions.

“I don’t think it would be possible for Russia to have a full-scale invasion and war in a European country and at the same time mobilize in their own country without help from China,” Ms. Frederiksen said. “We need to push China more, because you cannot help Russia in invading a European country.”

Mr. Zelensky flew to the United States on Sunday and visited a factory in Scranton, Pa., that makes 155-millimeter howitzer artillery shells. He thanked the workers for their efforts in supporting Ukraine.

Mr. Zelensky said in the interview that he planned to have meetings in Washington after his United Nations visit.

Violence between Israel and Hezbollah, the Iranian-backed Lebanese militia, has escalated over the last week as the two groups ramp up tit-for-tat strikes across the Lebanese border.

Hezbollah’s leaders have vowed to retaliate against Israeli strikes, saying the group will continue its attacks on Israel until a cease-fire deal is reached between Israel and Hamas, Hezbollah’s ally.

More than 40,000 people have been killed in Gaza during the first 11 months of the war, according to the Gazan Health Ministry, which does not distinguish between civilians and combatants. Many more have been displaced. Lebanon had remained relatively unscathed until recently, when Israel turned its attention to Hezbollah.

Israel pummeled Lebanon with airstrikes on Monday, the deadliest day in the country since at least 2006. The attack left more than 550 dead and more than 1,500 injured. The Israeli military said in a statement on Tuesday that its air force hit about 1,600 Hezbollah targets in Lebanon on Monday and was continuing to strike the country.

Israel’s escalation comes after hundreds of pagers and walkie-talkies owned by Hezbollah members exploded across Lebanon last week, killing more than 30 people, including two children, and injuring thousands. Israel did not explicitly claim responsibility, but Yoav Gallant, the Israeli defense minister, said that the “center of gravity” of Israel’s military effort, which had concentrated on eliminating Hamas in Gaza, was “moving north.”

Israel bombarded Lebanon throughout the weekend. On Friday, Israel hit Beirut, the Lebanese capital, killing several top Hezbollah commanders, including one of the group’s most senior leaders, according to Israeli officials. The attack also flattened a residential building, killing and wounding dozens of civilians.

On Sunday, Hezbollah launched more than 100 missiles, rockets and drones into Israel, striking around 30 miles inside the country’s borders in its deepest attack since last October.

António Guterres, the U.N. secretary-general, called on Monday for an immediate end to hostilities between Israel and Hezbollah, with his spokesman, Stéphane Dujarric, saying in a statement that, “there is no military solution that will make either side safer.”

On Tuesday, Danny Danon, Israel’s ambassador to the U.N., said Israel was not eager to start a ground invasion in Lebanon. “We don’t want to send our boys to fight in a foreign country. But we are determined to protect the civilians of Israel. We prefer a diplomatic solution — if it’s not working, we are using other methods to show to the other side that we mean business.”