At least 37 people have been killed since Tuesday and thousands of others wounded in Lebanon by coordinated explosions of pagers and walkie-talkies believed to have been booby-trapped by Israel. Those killed appear largely to have been members of Hezbollah, but also include several children.

“The explosions in Lebanon seem to have been targeted, but had heavy, indiscriminate collateral damages among civilians: children were killed,” the European Union’s top diplomat, Josep Borrell Fontelles, said in a statement condemning the attacks.

Other governments have reacted more cautiously. Secretary of State Antony J. Blinken said on Wednesday that the United States was still “gathering the facts” about the blasts.

The legal debate is complicated by the fact that while Hezbollah has blamed the Israelis for the attacks and American officials and many international experts say they are responsible, Israel itself has not publicly claimed responsibility.

Volker Türk, the U.N.’s high commissioner for human rights, on Wednesday called for an investigation, saying the people behind the attacks could not have known who might be holding the devices when they exploded.

A 9-year-old girl, Fatima Abdullah, was killed on Tuesday when she picked up a pager that was beeping on her kitchen table to take it to her father, the girl’s aunt said. A second child was also killed, Lebanon’s health minister said on Wednesday.

“Simultaneous targeting of thousands of individuals, whether civilians or members of armed groups, without knowledge of who was in possession of the targeted devices, their location and their surroundings at the time of the attack violates international human rights law,” Mr. Türk said in a statement.

In practice, no one is likely to be prosecuted under international law, given the secretive nature of the operation and the long history of covert actions in the Middle East — many ascribed to Israel — whose perpetrators have escaped accountability.

That has not hindered a lively debate.

Some experts on the law of armed conflict, or international humanitarian law, argue that Mr. Türk’s analysis overlooks the fact that the laws of war apply in this situation.

“Human rights are always present but are superseded in this case by the very specific laws intended for armed conflict,” Gary Solis, a retired Marine and Marine judge advocate who ran West Point’s law of war program. He is the author of “The Law of Armed Conflict: International Humanitarian Law in War.”

Although it may seem callous, Mr. Solis said, the reality is that international humanitarian law attempts to minimize civilian harm in war but allows for “collateral damage.”

The first question, he said, is whether the fighting between Hezbollah and Israel constitutes an armed conflict. He contends that it does, based on continual exchanges of fire between the two over the past 11 months.

But Mr. Solis also noted that analyzing these incidents is “like walking through a thick forest and trying to push aside a bunch of brambles” to answer questions that depend on specifics that are not known.

The key questions surrounding the legality of the attacks mainly relate to civilian harm.

Brian Finucane, a senior adviser with the International Crisis Group research institute and a former State Department legal adviser, said several factors could determine whether the attacks had violated the law of armed conflict or international humanitarian law.

In a post on the Just Security blog, Mr. Finucane wrote that among the factors were whether the carriers of the pagers were the intended targets and whether they were legal targets. Other considerations are whether the expected harm to civilians was excessive in relation to the military advantage, he said, and whether feasible precautions were taken to protect civilians from harm.

“Did this action constitute an indiscriminate attack or a series of such attacks?” Mr. Finucane wrote.

Mr. Solis, who is critical of Israel’s conduct of the war in the Gaza Strip, argued that in this case, the remote device attacks seem to be legal because the weapons did not cause “superfluous damage” or “unnecessary suffering” — both legal terms — and appeared designed to target individual Hezbollah operatives.

“Were they lawful targets?” asked Mr. Solis. “Probably, based on what we know. But we’re operating in the land of shadows.”

He noted, too, that the legality of booby traps may depend on how they were made.

“In World War II, we’d booby trap binoculars,” Mr. Solis said. “The Nazis would pick them up and they’d explode.” But it would have been illegal to build a factory that manufactured booby-trapped binoculars, he said.

It is a fine distinction but a critical one. “A combatant may booby-trap a camera which is in fact a camera, but he may not manufacture booby traps that appear to be cameras,” he said.

Eugene Kontorovich, a law professor at George Mason University in Fairfax, Va., defended the legality of the attacks against Hezbollah, saying they were a “classic act of sabotage.” To argue otherwise, he said in a social media post, would also call into question acts of sabotage against the Nazis, said Mr. Kontorovich, who is Israeli.

Human Rights Watch questioned the legality of the attacks.

“The use of an explosive device whose exact location could not be reliably known would be unlawfully indiscriminate, using a means of attack that could not be directed at a specific military target and as a result would strike military targets and civilians without distinction,” the group said in a statement.

There are other concerns.

There is widespread fear in Lebanon that, beyond pagers and walkie-talkies, other devices may be rigged. Instilling this kind of fear also raises legal questions, some experts said.

“Acts or threats of violence the primary purpose of which is to spread terror among the civilian population are prohibited,” Alonso Gurmendi Dunkelberg, a fellow in human rights at the London School of Economics, wrote on social media.

Anushka Patil contributed reporting

During the review, legal experts representing the Israeli government argued that Palestinian armed groups were to blame for civilian deaths in Gaza, including those of children. Israel has long said that Hamas militants embed themselves among civilians, using innocent people as human shields.

But the U.N. committee said those factors were not enough to justify Israel’s conduct.

“They were not, in our view, facing up to the reality that 17,000 children are dead and that there have been repeated attacks on schools and hospitals,” Anne Skelton, chairwoman of the U.N. committee, told journalists in Geneva, noting that “children are always civilians.”

Gazan health authorities have reported that children have made up some 40 percent of the more than 40,000 people killed in the war since the Oct. 7 Hamas-led attack on Israel.

“The outrageous death of children is almost historically unique. This is an extremely dark place in history,” said Bragi Gudbrandsson, vice chair of the U.N. committee. He added, “I don’t think we can identify any measure that was taken to save children’s lives in this military operation in Gaza.”

Israel, in a statement from its mission to the U.N. in Geneva, said the committee had shown little interest in the rights of Israeli children and deplored its failure to call for the release of two child hostages still being held by Hamas, saying it was evidence of a politically driven agenda. Hamas took some 250 hostages on Oct. 7.

Israel also asserts that the Convention on the Rights of the Child does not apply to its operations in occupied territories or areas of armed conflict, an argument rejected by the committee in line with the position of the U.N. General Assembly and the International Court of Justice.

The committee also expressed alarm over Israel’s arrest and prolonged detention of Palestinian children in Gaza and the West Bank.

In June, the U.N. secretary general’s annual report on children in armed conflict included Israel as well as Hamas and Palestinian Jihad, another militant group that operates in Gaza, on the list of countries and armed groups that harmed children.

“The only real way to serve children’s rights in this situation is a cease-fire,” Ms. Skelton said.

“This retribution will come. Its manner, size, how and where — these are things we will certainly keep to ourselves, in the narrowest circles even among us,” he said.

As Mr. Nasrallah spoke, Israeli fighter jets swooped low over Beirut, accompanied by sonic booms that sent residents running from their homes.

The attacks were widely attributed to Israel, which has declined to publicly take responsibility. Booby-trapped wireless devices belonging to Hezbollah members detonated across the country, often in their owners’ hands and pockets. More than 2,900 people were wounded; the breakdown between civilians and combatants remained largely unclear.

The coordinated attacks raised tensions in a region already on edge. After the Hamas-led attack on Oct. 7, which triggered the war in Gaza, Israel rushed soldiers to its northern border, fearing a similar invasion by Hezbollah. (Hamas and Hezbollah are both backed by Iran and dedicated to the destruction of Israel.)

The following day, Hezbollah fighters began firing missiles and drones at Israel, prompting Israel to respond with airstrikes and artillery fire.

Nearly a year later, the situation remains a deadly stalemate. Both sides regularly conduct cross-border attacks, and more than 150,000 Israelis and Lebanese have fled border communities that have become free-fire zones. Israeli leaders have felt increasing pressure from roughly 60,000 displaced Israelis to take more aggressive military action against Hezbollah.

In a mostly defiant speech broadcast from an undisclosed location, Mr. Nasrallah conceded that this week’s attacks had been “a severe and cruel blow.” But he said even Israel’s “technological superiority” would not deter Hezbollah from continuing to fire missiles and drones at Israel in solidarity with Hamas in Gaza.

He accused Israel of violating international law by detonating the devices in civilian areas, including hospitals. And he said Hezbollah had formed internal committees to investigate the security breach that allowed Israel to plant explosives in the group’s communication devices.

Mr. Nasrallah told his audience that Hezbollah had received messages that the goal of the Israeli operation was to force the group to stop its military operations in support of Hamas or face more Israeli attacks. He said Hezbollah would not bow to pressure.

“No matter which future awaits the region — the resistance in Lebanon will not stop supporting and backing the people of Gaza,” Mr. Nasrallah said.

Israeli officials have increasingly suggested in recent days that they intend to ratchet up their military operations in Lebanon to fend off Hezbollah.

On Wednesday night, Benjamin Netanyahu, the Israeli prime minister, released a short video in which he vowed that Israel would facilitate the safe return of displaced Israelis to their homes along the country’s northern border.

Mr. Nasrallah mocked Mr. Netanyahu’s pledge, saying Hezbollah would not allow Israelis to return to their border towns until Israel ends its war in Gaza.

“Do whatever you like. You are incapable of achieving it,” said Mr. Nasrallah. “Military escalation, killing, assassinations, and total war — none of them will bring those residents back to the border,” he added.

Analysts said the attacks humiliated Hezbollah, piercing its reputation as one of Israel’s most sophisticated foes, and seemed to necessitate a forceful response. But retaliating too forcefully could ignite a wider war with Israel at a time when many Hezbollah fighters were apparently wounded by the attacks.

In his address, Mr. Nasrallah sought to downplay the impact of the attacks on the armed group’s readiness for a full-blown war. Hezbollah’s fighting capabilities “did not shake or tremble” and its command and control structure was still intact, he said.

Euan Ward contributed reporting.

The prosecutor’s office in Tel Aviv asked that the suspect, a Jewish Israeli businessman named Motti Maman, 73, from the city of Ashkelon near the border with Gaza, remain jailed until the end of the legal proceedings.

The indictment said the plan was being hatched in retaliation for the assassination in the Iranian capital, Tehran, in July of Ismail Haniyeh, a top leader of Hamas. Iran has accused Israel of hiding the explosive device that killed Mr. Haniyeh in an apartment where he was staying and has vowed to retaliate. Israel has not claimed responsibility for the attack.

Mr. Maman at one time lived in Turkey, according to Kan, Israel’s public broadcaster. He is charged with contact with a foreign agent and unauthorized entry into an enemy state.

It appeared from the indictment that the plan was not far advanced.

Kan cited the man’s lawyer, Eyal Besserglick, as saying that his client had made an error of judgment and that he was now cooperating with the authorities.

In April, decades of clandestine conflict between Iran and Israel burst into the open when Tehran fired hundreds of missiles and drones at Israel, the vast majority of them intercepted. The Iranian attack was done in retaliation for a strike by warplanes on the Iranian embassy complex in Syria, that killed senior commanders overseeing Iran’s covert operations in the Middle East.

Among the Iran-backed militant groups fighting Israel are Hezbollah in Lebanon, Hamas in Gaza and the Houthis in Yemen.

“You see the sophistication of the technological minds of Israel and the total failure of the political leadership to carry out any moves of consequence,” said Ehud Olmert, a former Israeli prime minister.

“They are too preoccupied and obsessed by their fears to do anything on a broader strategic basis,” Mr. Olmert said.

Israel’s security services have infiltrated and sabotaged Hezbollah’s communications networks by blowing up pagers and other wireless devices this week, but Israel’s leadership appears uncertain about how to contain the group in the long term. Israel has conducted several clandestine missions and assassinations inside Iran, most recently of the Hamas leader Ismail Haniyeh by infiltrating a guesthouse protected by the Iranian security establishment. At the same time, it has avoided making the political concessions necessary to forge formal alliances with most of Iran’s opponents in the region.

Its commandos have freed several hostages from captivity through complex special operations, even as its politicians have failed to secure a wider deal to rescue more than 100 others still held in Gaza. And while Israel’s world-leading Air Force has pounded Gaza, destroying much of the territory’s urban fabric and killing top Hamas commanders like Muhammad Deif, the Israeli government has not issued a detailed and viable plan for Gaza’s postwar future.

The result is a slow and repetitive military campaign in Gaza in which Israeli soldiers are repeatedly capturing and then withdrawing from the same pockets of land, with no mandate to either hold ground or initiate a transfer of power to a different Palestinian leadership.

Israel’s campaigns have come at considerable cost. By killing tens of thousands of Gazan civilians as well as several hundred Lebanese in its strikes on enemy combatants, Israel has prompted international outcry, drawn accusations of genocide at the International Court of Justice and tarnished its global standing without conclusively destroying Hamas, let alone Hezbollah.

For now at least, Israel’s choices have also undermined its chance to forge diplomatic ties with Saudi Arabia, the most influential Arab country and one that could provide Israel with an extra diplomatic and even military buffer against Iran and Hezbollah. Talks to normalize relations with Riyadh have stumbled amid Israel’s refusal to allow Palestinian sovereignty in Gaza and the West Bank after the war.

For some, the scrambled thinking is partly derived from the shock of Hamas’s Oct. 7 attack on Israel. The attack was the bloodiest day in Israel’s history and may have left Israel’s leaders seeking short-term wins to atone for their lapses that day, at the expense of long-term planning for Israel’s future. With many Israelis traumatized by the attack, their leaders risk losing popularity and further tarnishing their legacy by promoting contentious compromises to bring Israel’s various wars to a close.

“Tactical successes can be obtained by professionals, but large-scale achievements have to be achieved by leaders,” said Itamar Rabinovich, a former Israeli ambassador to Washington. “They must be able to bite their tongue, go against the grain, take unpopular decisions and political risks.”

For Benjamin Netanyahu, the Israeli prime minister, Israel’s security must be prioritized at all costs, and Hamas and Hezbollah must be fully defanged — in part to restore the sense of deterrence and invincibility that Israel lost on Oct. 7 — before diplomatic compromises can be reached.

But to Mr. Netanyahu’s critics, true security cannot be achieved without a diplomatic vision that Israel’s allies and potential allies can accept; they argue that Israel’s successful operations against Hamas, Hezbollah and Iran will only have limited effect in the long term if they remain divorced from a coherent national strategy. According to his opponents, Mr. Netanyahu has allowed political considerations — principally his need to prevent the collapse of his fragile coalition government — to supersede strategic decisions that are opposed by his coalition allies.

Mr. Netanyahu’s grip on power is dependent on a group of far-right lawmakers who are opposed to the kinds of compromises necessary to reach an endgame in Gaza and Lebanon.

Those lawmakers have threatened to collapse Mr. Netanyahu’s coalition if he agrees to a truce in Gaza that leaves Hamas in power. They also oppose plans to hand power to Hamas’s main Palestinian rival, Fatah.

In turn, the standoff in Gaza has led to the extension of the war along the Israel-Lebanon border, where Hezbollah says it will continue fighting until a truce is reached between Israel and Hamas.

Mr. Netanyahu’s allies say the attacks this week in Lebanon, coupled with the deployment of more troops to the Lebanon border, show a clear strategic effort to use increased military action to force Hezbollah to compromise.

“Even though these are tactical moves, it’s part of a bigger plan,” said Nadav Shtrauchler, a political strategist and former adviser to Mr. Netanyahu. After months of contained conflict along the Israel-Lebanon border, Mr. Shtrauchler said, “We’re going to go strong at Hezbollah.”

To others, the moves still feel inconclusive, stopping short of a decisive end to the deadlock through either force or diplomacy. On the one hand, Mr. Netanyahu has avoided ordering a ground invasion of Lebanon. On the other, he has rejected a truce in Gaza that could end the Lebanon war through mediation.

“Where is he going? How does he end the war?” asked Mr. Rabinovich, the former ambassador. “All these fundamental questions have not been answered, and in some cases not even asked in the public discourse.”

To Mr. Olmert, the former prime minister, Israel’s lack of strategy extends far beyond Mr. Netanyahu.

The problem is rooted, Mr. Olmert said, in a reluctance across Israeli society and its establishment to address or sometimes even acknowledge a conundrum within Israel — the question of Palestinian sovereignty.

“There is no endgame on any issue without the Palestinians,” Mr. Olmert said.

Many Israelis now reject the idea of a Palestinian state because they feel a sovereign Palestine, shorn of Israeli supervision, would be more able to mount the kind of attack that Hamas initiated on Oct. 7.

Even centrist and left-leaning leaders mostly see the resumption of peace talks as a non-starter, given that one of the two leading Palestinian factions, Hamas, killed more than one thousand Israeli civilians less than a year ago and the other, Fatah, is weak and discredited among much of the Palestinian population.

Without agreeing to a pathway to a Palestinian state, it will be difficult for Israel to solve most of its other strategic binds, Mr. Olmert said.

For example, it will be harder to plan for a postwar Gaza without showing more flexibility on Palestinian sovereignty, Mr. Olmert said: The only feasible Palestinian alternative to Hamas is the Palestinian Authority, the Fatah-dominated institution that administers parts of the West Bank.

By allowing the Palestinian Authority to govern in both Gaza and the West Bank, Israel would in effect reestablish political contiguity between the two territories, making it easier to form a Palestinian state that spans both places.

Without at least some progress toward Palestinian statehood, it will also be harder for Israel to forge formal ties with Saudi Arabia, since the Saudi leadership has made clear that concessions to the Palestinians are a prerequisite for normalization. And by forging such an alliance, Israel could firm up its standing in the region and make Iran and its Hezbollah proxy warier of antagonizing Israel, since Saudi Arabia also shares Israel’s wariness of Tehran, Mr. Olmert said.

“Hezbollah and Iran won’t suddenly become Zionists, but it will change the balance,” said Mr. Olmert. “It will make life for Israel much easier to deal with such challenges.”

Rawan Sheikh Ahmad and Johnatan Reiss contributed reporting.

For decades, the leaders of Saudi Arabia, like those of most other Arab countries, refused to recognize Israel without the creation of a state for the Palestinians. But after 2020, when four Arab states established formal ties with Israel in agreements brokered by then-President Donald J. Trump, Prince Mohammed became the first Saudi leader to talk openly about the possibility of Saudi Arabia doing the same.

In an interview with Fox News last September, he called a potential agreement “the biggest historical deal since the end of the Cold War” and said it would require “a good life for the Palestinians” but did not mention Palestinian statehood.

His statement on Wednesday followed a general hardening of official Saudi rhetoric toward Israel since the start of the Gaza war in October.

“We renew the kingdom’s rejection and strong condemnation of the crimes of the Israeli occupation authority against the Palestinian people,” Prince Mohammed said, delivering remarks on behalf of his father.

The crown prince’s statement came nearly a month after President Mahmoud Abbas of the Palestinian Authority visited him in Riyadh.

Until Hamas sparked the Gaza war with a devastating attack on Israel on Oct. 7, both Israeli and Saudi officials had been indicating they were moving toward a deal.

Saudi Arabia has been seeking security guarantees, including a defense pact with the United States and assistance with a civilian nuclear program as part of any agreement. During the Fox News interview, Prince Mohammed stated that Riyadh was “getting closer” to an accord.

However, since the Gaza war broke out, Saudi Arabia has insisted on the need for an “irreversible track” to Palestinian statehood.

This month, Secretary of State Antony J. Blinken said he still hoped to finalize an Israeli-Saudi deal before the end of President Biden’s term. “I think if we can get a cease-fire in Gaza, there remains an opportunity through the balance of this administration to move forward on normalization,” Mr. Blinken said.

Palestinian officials welcomed the crown prince’s comments, saying that they supported the position of the Ramallah-based Palestinian leadership.

“This is an affirmation that the Saudi position is enduring in its support of the Palestinian cause,” Mahmoud al-Habbash, the religious affairs adviser to Mr. Abbas, said in an interview on Thursday. “We’re reassured about the Saudi stance, which is a cornerstone of the Arab and Islamic world’s position.”

After two consecutive days of attacks — in which hand-held communication devices detonated across Lebanon, killing dozens and injuring thousands — the tiny Mediterranean nation was rattled. The explosions were an apparent attack by Israel on members of Hezbollah, the powerful Lebanese militant group. But that did not stop others from fearing for their lives.

“Maybe tomorrow lighters will explode, too,” said Hussein Awada, 54, who works as a private driver. “If you want to light a cigarette, it will just explode in your hand.”

On Wednesday, Mr. Awada witnessed the second wave of attacks on Hezbollah, when walkie-talkies owned by the group’s members exploded, a day after thousands of Hezbollah pagers blew up. He had watched as a man had his hand blown off by the two-way radio he was holding.

The blasts were part of an elaborate Israeli operation to infiltrate Hezbollah’s supply chain, according to officials briefed on the attack, though Israel has neither confirmed nor denied any role in the explosions. On Thursday, Lebanon’s civil aviation authority banned pagers and walkie-talkies from all flights leaving Beirut’s airport.

The attacks have further ratcheted up fears of a major war between Israel and Hezbollah, which have exchanged thousands of missiles and rockets since the war in Gaza began in October.

To Mr. Awada, the clandestine work that went into booby-trapping Hezbollah’s devices and the apparently seamless coordination of the attack were like a work of fiction.

“I saw stuff today that you can only see in movies,” he said.

At least 32 people have died in the attacks, a significant number of which Hezbollah confirmed as members, although children and health workers were among the dead. More than 3,000 other people were confirmed to have been wounded in the attacks since Tuesday afternoon, many maimed with hand or face injuries.

Hezbollah is Lebanon’s dominant military and political force and is designated a terrorist group by Israel and the United States. But for many Lebanese, it is an organization with deep roots in society, providing a roster of social services and welfare programs across the country in the place of the ailing state.

Everyone, it seems, had some connection to the dead and wounded.

“In Dahieh, it’s hard to find anyone who doesn’t know someone who was affected,” said Mortada Smaoui, 30, a local business owner, using the Arabic name for Beirut’s Hezbollah-dominated southern suburbs. “Either it’s your friend, or a relative or a friend of friend, so you can clearly feel the sorrow and the anger.”

After the first attack on Tuesday, Mr. Smaoui rushed to the nearest hospital, heeding calls for volunteers to donate blood. There he witnessed the chaos firsthand: bodies being carried away in blood-soaked sheets, family members frantically searching for their loved ones and the wails of injured victims who were being turned away because of a lack of beds.

Still, Mr. Smaoui said after the first attack that it had shown Lebanon at its best, with citizens from across the country’s sectarian patchwork coming together to clear roads and give blood, so much so that hospitals had to turn away prospective donors.

“I felt unity,” he said.

That sentiment was shattered on Wednesday when he was once again confronted by the carnage.

“There are buildings burning right now in front of me,” Mr. Smaoui said in the minutes after the second round of explosions, staring up at an apartment block engulfed in flames.

Dr. Salah Zeineddine, the chief medical officer at the American University of Beirut Medical Center, said the attacks were “beyond any catastrophe” he had dealt with before. Nearly 200 patients were rushed into the hospital in just three hours on Tuesday after the first wave of explosions, quickly swamping it.

“There have been so many catastrophes and mass casualties in Lebanon, but this was the first time we have seen so many casualties in such a short period of time,” Dr. Zeineddine said.

The wounded were still being tended to on Wednesday when the second round of blasts struck.

“People in the streets were screaming,” Adnan Berro, 61, said. “It was chaos. There was so much blood — on their hands, their faces, everywhere.”

“I have never seen anything like it,” he said.

Hezbollah said that it had launched exploding drones at an Israeli military base and at artillery positions. The Israeli military said that there were no immediate reports of injuries, but that firefighters were working to battle blazes caused by drones.

Israel’s military said it had struck infrastructure belonging to Hezbollah at six sites, as well as a weapons storage facility near the town of Khiam in southern Lebanon.

Since the Oct. 7 Hamas-led attack on Israel started the war in Gaza, Hezbollah has fired thousands of missiles and drones at Israel in support of Hamas, which like Hezbollah is backed by Iran.

Israel has struck back, assassinating senior members of the militia and striking thousands of targets. This week’s attacks on Hezbollah members, which have been widely attributed to Israel, have escalated concerns that the conflict could turn into a larger war.

More than 100,000 people have fled their homes in southern Lebanon, and Israel has ordered the evacuation of more than 60,000 people in the north of the country.

Euan Ward contributed reporting.

Icom said in a statement Thursday that it had not shipped any of the IC-V82 radios from its plant in Wakayama, Japan, in roughly a decade. But the company has long warned of what it called a surge in counterfeit IC-V82 transceivers.

Japan’s chief cabinet secretary, Yoshimasa Hayashi, said on Thursday that the Japanese government was looking into the matter.

At least 25 people were killed and over 600 injured on Wednesday when walkie-talkies owned by Hezbollah members exploded across Lebanon, the country’s health minister said. It was unclear where Hezbollah purchased the devices that exploded.

Icom, founded in 1954, sells radios and other products in more than 80 countries and has about 1,000 employees. According to the company, it has supplied electronics gear to public safety organizations and the U.S. Department of Defense and Marine Corps.

Icom said it has no inventory of the IC-V82 model and has issued warnings saying that “almost all” IC-V82 radios available for purchase are counterfeit. Icom said it has taken legal action against counterfeit manufacturers and has warned about fake models since at least 2020.

A day before the radio explosions, blasts from pagers killed at least 12 people and wounded over 2,700 others in Lebanon. Israel has neither confirmed nor denied any role in the explosions, but 12 current and former defense and intelligence officials briefed on the attack say the Israelis were behind it.

Companies that make two-way radios say the devices typically have a life span of about five to seven years, though that can depend on their usage.

“Copies of these models are floating in the market,” Icom has said in warnings posted online. Authentic products have a hologram label that says “Icom” and “genuine,” according to the company.

Icom said on Thursday that because the devices that exploded in Lebanon were not fixed with the counterfeit-prevention sticker, it was not possible to confirm whether they had originated with the company. Icom declined to specify how it determined that the radios did not have the label.

The company said it sells products only to authorized distributors and that it upholds strict export controls based on regulations set by Japan’s economy ministry. The company said it would continue to provide updates when it receives new information.

Counterfeit versions of the radios are at risk of catching fire or exploding because of battery malfunctions, Icom said. Many are labeled “made in China,” according to Icom. The company said that all of its radios are produced at factories in Japan.

The devices were readily available online on Thursday. At least two vendors on Taobao, a Chinese e-commerce marketplace, were selling what they said were Icom IC-V82 walkie-talkies, one for $32 apiece and the other for $34. Three vendors were selling what was listed as the Icom walkie-talkie on another Chinese e-commerce platform, JD.com, and quoted prices of $35, $55 and $104.

A website that aims to connect Chinese suppliers with buyers overseas, available in over a dozen languages, offered the IC-V82 for $38 each if purchased in an order of 1,000 or more.

Keith Bradsher contributed reporting from Beijing and Li You contributed research.

Mr. Gallant’s comments came just after Israel’s cabinet officially adopted a new, formal war goal this week: ensuring that tens of thousands of residents of northern Israel who have been displaced by attacks from Hezbollah can return safely to their homes.

Later on Wednesday, as the exploding attacks continued, Israel’s prime minister, Benjamin Netanyahu, issued a video statement emphasizing the same goal. “I already said that we would return the residents of the North securely to their homes, and that is exactly what we will do,” he said.

Hezbollah, a militant group designated as a terrorist organization by the United States, has been targeting northern Israel with rockets and drones since last year in solidarity with Hamas and its war against Israel in Gaza. Both militant groups are supported by Iran and want to eliminate the state of Israel.

The daily exchange of fire between Hezbollah and Israel has been destructive, disruptive and sometimes deadly for Israelis and Lebanese living along the border, and it has raised concerns among world leaders that a wider regional war could break out and draw in Iran.

For months, international diplomats have been working to avert that outcome. There was, until recently, hope that a cease-fire agreement between Israel and Hamas to end the fighting in Gaza in exchange for the release of dozens of hostages kidnapped from Israel would also resolve the conflict with Hezbollah. But the cease-fire talks have stalled, and tensions between Israel and Hezbollah have been steadily mounting in recent months.

In July, Israeli forces struck a suburb of Beirut, Lebanon’s capital, and assassinated a top Hezbollah commmander, Fuad Shukr. The Israeli military said Mr. Shukr’s killing was in response to a rocket attack on the Israeli-controlled Golan Heights that killed a dozen children in Majdal Shams, a Druze Arab village, though Hezbollah did not claim responsibility for that strike. Hezbollah vowed to avenge Mr. Shukr’s death, and in late August it launched about 300 rockets into Israel, claiming that it struck an Israeli military target.

Military experts have noted that so far Israel and Hezbollah have exercised relative restraint. But there are fears that the conflict may escalate if a diplomatic resolution does not come soon. Israeli officials on Wednesday appeared to be signaling that such an escalation was fast approaching.

The Israeli military’s chief of staff, Lt. Gen. Herzi Halevi, on Wednesday reviewed contingency plans for a possible conflict with Hezbollah on Israel’s northern border, according to a military statement.

“We are very determined to create the security conditions that will return the residents to their homes, to the communities, with a high level of security, and we are ready to do all that is required to bring about these things,” General Halevi said, adding that “at each stage, the price for Hezbollah must be high.”

Still, Israeli leaders are bracing for a difficult fight. In his address on Wednesday, Mr. Gallant said that Hezbollah would be a more challenging opponent than Hamas had been in Gaza. “It’s not Hamas,” he said. “This is something else, and we need to prepare for this accordingly and take it into account.”