Mr. Cardin also celebrated the return of Vladimir Kara-Murza, an activist and journalist who has worked with a number of members of Congress on legislation related to human rights abuses in Russia. “Equally important is the release of Russian democracy advocates and antiwar activists, including my friend Vladimir Kara-Murza,” he said in a statement. Mr. Kara-Murza, who holds an American green card, writes for The Washington Post.

Republican leaders also shared reservations about the continued use of prisoner exchanges and questioned the effectiveness of “hostage diplomacy.”

“I remain concerned that continuing to trade innocent Americans for actual Russian criminals held in the U.S. and elsewhere sends a dangerous message to Putin that only encourages further hostage-taking by his regime,” Representative Michael McCaul, Republican of Texas and the leader of the House Foreign Affairs Committee, said in a statement.

That same apprehension was echoed by his party’s House and Senate leaders, Speaker Mike Johnson and Senator Mitch McConnell.

“Without serious action to deter further hostage-taking by Russia, Iran, and other states hostile to the United States, the costs of hostage diplomacy will continue to rise. As we renew our call for the return of all persons wrongfully detained by the Kremlin, we recognize that trading hardened Russian criminals for innocent Americans does little to discourage Putin’s reprehensible behavior,” the top Republican’s on Capitol Hill said in a joint statement.

Despite disagreement on tactics for securing the release of detained Americans, there was consensus that returning all political prisoners should remain a top priority.

The family of Marc Fogel, an American teacher imprisoned on drug charges in Russia, expressed disappointment that he was not part of the swap.

Ms. Navalnaya, who has said she would continue her husband’s work in leading the opposition, said on X that the effort should continue to free others not included in Thursday’s exchange.

The office of Ms. Harris issued a statement Thursday to say that the vice president had called Ms. Navalnaya to welcome the release of political prisoners and to say that she would continue to support those “fighting for freedom in Russia and around the world.”

Mr. Navalny, who was one of the Kremlin’s fiercest critics, was serving multiple sentences at the time of his death that would most likely have kept him in prison until at least 2031.

Originally, the possible release of Mr. Navalny from a Russian penal colony prompted negotiations about an exchange for Vadim Krasikov, the Russian assassin who was serving a life sentence in a German prison before being released in Thursday’s swap. That possible trade ended when Mr. Navalny died, but several Russian activists who worked with him were included in Thursday’s exchange.

The Americans involved in the swap included Evan Gershkovich, a Wall Street Journal reporter; Alsu Kurmasheva, a Russian American editor for Radio Free Europe/Radio Liberty; and Paul Whelan, a former U.S. Marine arrested in 2018.

They had “shown incredible courage,” Ms. Harris said in brief remarks on the tarmac in Houston before flying back to Washington.

“Over many years, President Biden and I and our team have engaged in complex diplomatic negotiations to bring these wrongfully detained Americans home,” Ms. Harris said. “We never stopped fighting for their release. And today, in spite of all of their suffering, it gives me great comfort to know that their horrible ordeal is finally over.”

She added that she had spoken with Yulia Navalnaya, the widow of Aleksei A. Navalny, the Russian opposition leader who died in custody in February and whose release was under negotiation when he died. His death scrambled the negotiation, and the swap.

“As I told her,” Ms. Harris said, “the United States stands with all of those who are fighting for freedom in Russia.”

Ms. Harris said that securing the release of more people wrongfully held abroad “is my solemn commitment to my fellow Americans, which I will always honor.”

The vice president did not stop to take questions from reporters before boarding Air Force Two. Late Thursday evening, Ms. Harris was scheduled to meet the released Americans with President Biden at Joint Base Andrews.

For Mr. Biden, the main focus of the day was celebrating the release of the prisoners alongside their family members at the White House, and reminding Americans that the release of wrongfully detained citizens had been a focus of his presidency — 70 have been freed since he took office.

Still, with Ms. Harris now the presumptive Democratic presidential nominee, Mr. Biden and his advisers made sure to point to Ms. Harris’s work as a partner in the effort.

“I would say they’ve learned from each other,” Karine Jean-Pierre, the White House press secretary, said of their relationship.

Ms. Harris’s aides have often cited her work at the Munich Security Conference as evidence of her growth in foreign policy. Jake Sullivan, the president’s national security adviser, told reporters on Thursday said that she had engaged with Olaf Scholz, the German chancellor, at the conference to talk about the release of prisoners.

Aware the United States had assessed there were two Russian nationals being held in Slovenia who could be key for a potential prisoner swap, Ms. Harris also told her team she wanted to meet with Prime Minister Robert Golob of Slovenia at the conference, according to a White House official who spoke on the condition of anonymity to discuss the meetings.

On Feb. 16, Ms. Harris and her national security adviser, Phil Gordon, met with Mr. Golob to discuss releasing the two Russians in exchange for freeing the detained Americans, including Mr. Gershkovich, the official said. The next day, after her regular scheduled bilateral meeting with Mr. Scholz, Ms. Harris asked Mr. Scholz to stay behind for a more restricted meeting with fewer aides in attendance.

The two leaders, each with a staff member alongside them, discussed the potential prisoner exchange. Ms. Harris conveyed that crucial to securing the release of Americans would be releasing Vadim Krasikov, a Russian convicted of murdering a Chechen former separatist fighter in Berlin in 2019 on orders of the Russian government.

Mr. Sullivan praised the vice president as “very much” a core member of “the team that helped make this happen.”

They talked for 10 minutes.

“It felt so new,” she said. “We hadn’t spoken on the phone for three years and two months.“

Mr. Pivovarov is a former director of Open Russia, an organization founded by the exiled former oil tycoon Mikhail Khodorkovsky that supports civil society in the country. Mr. Pivovarov was arrested in May 2021, accused of “participating in the activities of an undesirable organization.” In June 2022, he was sentenced to four years in prison.

Ms. Usmanova said that she found out on Saturday that her husband was no longer in the penal colony where he was serving out his sentence and at the time she did not understand what had happened. By Monday, when it became clear that a number of other political prisoners, including Ilya Yashin and Vladimir Kara-Murza had also disappeared, a sense of optimism started creeping over her.

“Honestly, it became easier for me because I started to feel hope that something good could be happening,” she said.

On Thursday, she purchased a ticket to Germany and hoped to reunite with Mr. Pivovarov, whom she married while he was behind bars, in July 2023. It would be their first time together outside of a Russian prison as a married couple. Inmates are not allowed to wear wedding rings, so she said she would be carrying her husband’s ring so that he could finally put it on.

Almaz Gatin found out that his wife, Lilia Chanysheva, was missing on Sunday when he brought a package to her. His post on the social media platform X was the first in the series of reports about Russian political prisoners disappearing. He said didn’t get his hopes up because last time Ms. Chanysheva was moved, it was for a retrial, which resulted in two more years added to her term.

Mr. Gatin said he is staying in Russia for now as he has to deal with their frozen assets, but of course he was happy. “There is a God.” he said. “In the end, you have to believe in God, love and in each other.”

Tatyana Kasatkina, the wife of Oleg Orlov, 71, an activist from one of Russia’s oldest human rights organizations, Memorial, said she was proud that her husband had withstood confinement despite his age and illness and that he “did not let prison break him.”

She had seen him in the past month, on a visit to the penal colony where he was serving a two-and-a-half-year sentence for “repeatedly discrediting the Russian armed forces.” As of Thursday, Ms. Kasatkina was in Russia and was not sure when she would be reunited with her husband.

Mr. Orlov has had a long career in Russia protesting war. He got his start as an activist in 1981 printing leaflets condemning the Soviet invasion of Afghanistan on a homemade printing press and posting them around Moscow. He spent subsequent decades defending the human rights of victims of Russian aggression inside and outside the country.

He decided to stay in Russia after the invasion of Ukraine in February 2022 even as many fled, and wrote an article comparing contemporary Russia to the society in George Orwell’s novel “1984.” Nearly a year later, he was convicted of “repeated discrediting” Russia’s armed forces. In his closing remarks, he condemned Russia’s descent into “totalitarianism” and “fascism.”

Like other family members, Ms. Kasatkina, too, said she first heard murmurs of a possible exchange on Monday, when her husband was no longer in the penal colony where he had been sent last month. Her hopes were confirmed when Mr. Orlov phoned briefly from Ankara, where the prisoner exchange took place.

“He called me so joyfully,” she said. “We spoke for about 20 seconds.” It was enough time for him to ask his wife if she knew what was happening.

“I said, ‘Of course, I have not been separated from my phone all day,’” Ms. Kasatkina said.

She added that she was proud that Mr. Orlov had not requested a pardon or admitted to any guilt.

“What he wrote to me was that if the president initiated a petition for pardon, it was not necessary,” she said. “‘I believe that I am not an enemy of Russia.’ That’s what he said.”

For the next quarter century, the most important operatives from the West and the Warsaw Pact, the Soviet Union’s military alliance, were exchanged there, until the last one in 1986 involving Natan Sharansky, the Soviet human rights advocate.

With the collapse of the Soviet Union in 1991 and the subsequent reunification of Germany, the bridge lost its greater purpose. The Havel River it crosses no longer formed part of the Iron Curtain dividing the East and West.

So when three Americans, several European nationals and Russian dissidents were swapped on Thursday for eight men and women whom the Kremlin wanted back from multiple countries, it took place at a Turkish airport.

Previous exchanges were not always cause for celebration. In March 1985, after a Russian sentry shot dead an American military intelligence officer named Arthur D. Nicholson Jr. in East Germany, his body was sent back across the bridge. The Soviet Union never ceded control of the structure to East Germany.

Like Evan Gershkovich, the Wall Street Journal reporter sentenced to 16 years in a Russian jail for espionage, many of those swapped on Thursday by the Kremlin were convicted on spurious grounds.

Numerous Russian opposition figures let go over the years were labeled spies by their own country, having been convicted of serving foreign governments — though their real crime was criticizing the Kremlin. This time around, Kremlin sympathizers began trotting out the same reason not to call them “political prisoners” as rumors of the exchange began to circulate.

One of the largest Cold War trades involved 29 people in June 1985, when 25 Westerners were let go in exchange for four people from the Soviet bloc, including Marian Zacharski, a notorious Polish spy.

If in the early decades the exchanges took place in darkness, with minimal publicity, the last one at the bridge occurred under the full glare of the world’s media. In February 1986, Mr. Sharansky was released across the bridge along with three Western operatives in exchange for five Soviet agents.

After the Cold War, such exchanges tended to take place in rather mundane locations, far less laden with symbolism. One of the largest, involving 14 people in 2010, transpired on the tarmac at Vienna International Airport in Austria.

The 10 people being released by the West included Anna Chapman, who had worked undercover as a real estate executive and socialite in New York, while the Russians let go of Sergei Skripal, a double-agent intelligence officer whom they later tried to poison in Britain in 2018.

The intrigue surrounding the exchanges on the Glienicke Bridge inevitably meant it featured often in movies, TV series and spy novels. One example, the 2015 film “Bridge of Spies” by Stephen Spielberg, starring Tom Hanks and Mark Rylance, dramatized the Powers-Abel exchange.

Perhaps no writer depicted Cold War tensions quite like John Le Carré. In the television version of “Smiley’s People,” British spymaster George Smiley, played by Alec Guinness, learns that his Soviet nemesis, Karla, the head of a fictional version of the K.G.B., has decided to defect across the bridge.

“That’s where he would choose, I suppose,” he said. “Yes, it’s natural.”

Susan C. Beachy contributed research.

Victor Bout, a convicted Russian arms dealer known as the “Merchant of Death” who was swapped for the American W.N.B.A. star Brittney Griner in 2022, said on Russia-24 that the exchange was “a big victory” for Russia.

“Our people returned, our heroes,” he said.

The report centered on the theme that Russia always fights to get its citizens back home. Konstantin Yaroshenko, a Russian pilot who was sentenced to a lengthy prison term in the United States on cocaine trafficking charges, said that “we never give up our guys.”

The former prisoners, commenting on a video of Evan Gershkovich and Paul Whelan being escorted to a Russian government plane in Moscow ready to depart for Turkey, said that the Americans looked well — a suggestion that the Americans were treated better than they had been while being held in Western prisons.

“Paul Whelan looks great, he doesn’t limp,” said Mr. Yaroshenko, who spent many years in an American prison, where he said he was repeatedly beaten and tortured.

“They look healthy, we are treating everyone in a humane way,” said Yelena Vavilova, a Russian “sleeper” agent who had worked undercover in America for decades before getting arrested in 2010 and later getting swapped back to Russia. She added, referring to opposition activists that were released: “Even those who wanted to subvert our society from within.”

Sergei A. Markov, a pro-Kremlin analyst, said in a post on Telegram that the Russian side recovered “honest officers” during the swap, while the United States got “political figures who served American interests.”

“By swapping them the U.S. recognized them as its political agents,” Mr. Markov said, referring to Russian opposition activists who were released to Germany.

In another post, Mr. Markov said that the swap was unlikely to signify that the bilateral relationship between Moscow and Washington was improving. On the contrary, he said, it meant that the relationship was at the lowest point in decades.

“It’s time to move away from the abyss,” Mr. Markov said.

“No one made this decision to deport a murderer sentenced to life imprisonment after only a few years of imprisonment lightly,” said the German chancellor, Olaf Scholz, on Thursday evening at the Cologne airport, minutes before a plane carrying many of the freed prisoners — including five German citizens — touched down.

Mr. Krasikov had been held in an undisclosed German high-security prison since being convicted in 2021, just months before the Russian invasion of Ukraine.

The returning Germans include one man who was detained at the St. Petersburg airport with six cannabis-laced gummy bears, a 19-year-old high school student and a former German Red Cross employee who had been sentenced to death on espionage charges in Belarus in June.

“In order to give 16 people a new life in freedom, we deported a convicted murderer to Russia,” said Marco Buschmann, Germany’s minister of justice in a statement. Mr. Buschmann ordered the release based on a little-used clause in the penal code, something he called a “bitter concession.”

The exchange could spell a rare moment of domestic success for Chancellor Olaf Scholz of Germany, who interrupted his summer break to welcome the prisoners. His willingness to engage diplomatically with Russia over the prisoners could boost his popularity among the many Germans who have become increasingly angry at the high sums the government is spending to support Ukraine in the war against Russia. Germany also hosts more than one million Ukrainian refugees.

The country’s support for Ukraine has become one of the major issues in three state elections next month, with many voters in the east opposed to it and two populist parties pushing for diplomatic talks with Russia surging in the polls.

Mr. Krasikov was found guilty by a Berlin court in 2021 for murdering Zelimkhan Khangoshvili in a park just miles away from the chancellery. The court found that he had shot Mr. Khangoshvili in the back.

The court convicted Mr. Krasikov in December 2021. The judge left no doubt that Mr. Krasikov had been sent by Moscow and found that he had been supported by a network in Germany. Shortly after the conviction, the German government called in the Russian ambassador to reprimand him, and it expelled two Russian diplomats.

At the time, Germany’s foreign minister, Annalena Baerbock, said the contract killing constituted “a serious violation of German law and the sovereignty of the Federal Republic of Germany.”

“Due to current developments, the Lufthansa Group is once again adjusting its service to the Middle East,” the German airline Lufthansa said on its website. The carrier had previously canceled flights to Beirut and is extending the pause by one week, through Aug. 12. Lufthansa also said it was suspending passenger and cargo flights to Tel-Aviv through Aug. 8.

Switzerland’s airline, SWISS, and Austria Airlines made similar announcements.

The cancellations came after a Lufthansa flight that was headed for Tel Aviv on Wednesday made an unexpected landing in Cyprus, deciding against entering Israeli airspace, the Israel Airports Authority said on Thursday.

Delta said on Wednesday that it was pausing flights to Tel Aviv from New York through Friday “due to ongoing conflict in the region.” But the carrier noted that travelers could still book flights to Tel Aviv through its partners, Israel’s El Al airline and Air France.

Similarly, United on Wednesday said in a statement that it was suspending flights to Tel Aviv “for security reasons” and would “continue to closely monitor the situation.”

The flight-tracking website Flight Aware on Thursday showed 18 flights had been canceled at the international airport in Tel Aviv on Thursday. According to the site, Air India also canceled all Tel Aviv flights, while other carriers appear to have halted some flights but not all. Air India did not respond to a request for comment.

The cancellations came as Israel’s national security council said in a new travel warning that Iran, Hamas and Hezbollah could seek to target Israelis abroad in the coming days, in retaliation for the killings of Fuad Shukr, a top Hezbollah commander, and Ismail Haniyeh, Hamas’s political chief. Israel announced it had struck Mr. Shukr not long after the airstrike in Beirut on Tuesday, but has not acknowledged or denied killing Mr. Haniyeh in Tehran, as it has been accused of doing by Hamas and Iran.

Israel had already boosted security for its athletes at the Paris Olympic Games, and they will likely receive heightened protection in the aftermath of the killings.

“As part of his role in the military wing, al-Ghoul instructed other operatives on how to record operations and was actively involved in recording and publicizing attacks” against Israeli troops, the statement said. “His activities in the field were a vital part of Hamas’ military activity.”

Walid al-Omari, the network’s Jerusalem bureau chief, said the claim Mr. al-Ghoul was a member of Hamas’ elite forces was “completely false.”

“Al Jazeera rejects the claim and the lies and considers them a blatant attempt to justify targeting journalists in Gaza,” he added.

Mr. al-Omari noted that Mr. al-Ghoul was previously arrested by the Israeli military in Al-Shifa Hospital in Gaza in mid-March, detained for 12 hours, then released “unconditionally.” He would not have been released, Mr. al-Omari said, if he was a member of Hamas who participated in the Oct. 7 attack. The Israeli military has said it had no record of formally detaining Mr. al-Ghoul.

On Wednesday, the network had condemned the Israeli military for killing two of its reporters in what it said was a “direct strike” on a car that the network said had been clearly marked as “press” and on correspondents who were also wearing vests that showed they were press.

Al Jazeera journalists protested their colleagues’ death on Wednesday. A video showed reporters in Gaza taking off the blue press vests intended to keep them safe and decrying the attack, with some lamenting that Mr. al-Ghoul had only sought to record the suffering of the Palestinian people.

The strike killed Mr. Al-Ghoul and his cameraman, Rami al-Rifee, in Shati camp in northern Gaza after the two reported from or near the house of the deceased Hamas political chief, Ismail Haniyeh, who was assassinated in Tehran on Wednesday, according to Al Jazeera.

The Committee to Protect Journalists has said the war in Gaza has led to the deadliest period for correspondents since it began gathering data in 1992, with at least 113 journalists and media workers among the more than 39,000 people killed in Gaza. That count includes Mr. al-Ghoul.

The Israeli military and security agency said they “are operating in order to eliminate terrorists” who participated in the Oct. 7 attack.

Adam Rasgon and Aaron Boxerman contributed reporting.

Three missiles struck the compound of the Dalal Mughrabi School in Gaza City’s Shejaiya neighborhood in the early evening, according to Mahmoud Basal, a spokesman for the Civil Defense.

An Al Jazeera journalist, Anas Al-Sharif, reported that the roof of the school building had collapsed on top of people who rushed in to try to help displaced people who had been sheltering inside. Footage he posted to social media showed people frantically digging through the rubble with rudimentary equipment.

The Israeli military said in its statement on Thursday that it had taken “numerous steps” to limit the risk to civilians and that it had used “precise munitions” in the strike. It has repeatedly bombed school buildings in Gaza or struck in their immediate vicinity, often saying the buildings were being used by Hamas fighters, claims that the group has long denied.

Since the war began nearly 10 months ago, Gaza’s education system has been devastated, and its schools have served as shelters for many of the 1.9 million people that the United Nations estimates have been displaced across the territory.

According to a U.N. assessment released on Sunday, nearly 85 percent of Gaza’s schools have been destroyed or damaged during the war, and more than half of the school buildings used as shelters have been directly hit.

Shejaiya, the Gaza City neighborhood where Thursday’s strike took place, suffered a devastating two-week raid by Israeli forces last month, during what the Israeli military said was an operation to suppress a Hamas insurgency there.

The Civil Defense said it recovered more than 60 bodies after Israeli troops pulled out, and Palestinians who had been ordered to leave by Israeli forces said they returned to find the neighborhood mostly uninhabitable, with many buildings destroyed.

People killed and injured in Thursday’s strike were taken to the Al-Ahli hospital, according to Wafa, the Palestinian Authority’s official news agency.

The Israeli army forced the hospital to close for several days during last month’s raid, according to the Episcopal Diocese of Jerusalem, which runs the medical center. The diocese said in a statement protesting the closure on July 8 that the hospital had faced heavy drone fire in its immediate vicinity and that one of its ambulances was fired on.

Its archbishop, Hosam Naoum, had pleaded at the time for “Israeli forces to permit us to continue our sacred ministry of medical care and healing.”

But although Mr. Nasrallah promised that Hezbollah would respond, he equivocated on the scope and nature of that retaliation.

“We have entered a new phase,” he said, speaking in a televised address during the funeral for Mr. Shukr. “You do not realize the red lines you have crossed,” warned Mr. Nasrallah, addressing Israel directly.

“The response will come, whether spread out or simultaneously,” he added.

Officials and diplomats across the Middle East had been looking to the speech for any indication of whether Hezbollah would alter course in its long-running conflict with Israel, either by escalating its military response or seeking to lower the pressure and avoid all-out war. The speech by Mr. Nasrallah on Thursday appeared to straddle that line.

Although he said the group and its allies were working on “a true response, not a show response as some are trying to suggest,” he added that Israel’s reaction would determine whether the war escalates.

The targeted Israeli strike in a Beirut suburb on Tuesday that killed Mr. Shukr also killed five civilians and wounded scores more, according to the Lebanese authorities.

The strike on Tuesday, which Israel quickly announced, was notable for several reasons, analysts said: It killed a high-ranking figure at the core of Hezbollah’s inner sanctum; it caused civilian casualties; and it hit less than three miles from downtown Beirut, Lebanon’s capital city, which had largely been spared direct violence. Some analysts said that Hezbollah could feel compelled to respond strongly because of those facts.

But Hezbollah has lowered the intensity of its attacks along Israel’s northern border since the strike on Tuesday, an indication that the group recognizes the stakes. Mr. Nasrallah said during his speech that he had ordered his fighters to remain calm, and that the group would resume operations on Friday. The retaliation for the killing of Mr. Shukr would come later, he added.

“The only things lying between us and you are the days, the nights and the battlefield,” said Mr. Nasrallah, again addressing Israel.

After Mr. Nasrallah finished his speech, Mr. Shukr’s coffin was carried onto the street outside and met a sea of mourners. The people frantically jostled back and forth to get closer to his body, pumping their fists in the air as the funeral procession moved through Beirut’s southern suburbs.

“No escape, no retreat,” the crowd shouted, repeating chants that echoed over the loudspeaker. Some held up pictures of fighters who had been killed. Others hoisted Hezbollah and Palestinian flags.

“We are not afraid of war,” said Fatima Nizan al-Din, 18, as she left the funeral. “We certainly expect an escalation.”

Aaron Boxerman contributed reporting from Jerusalem, and Hwaida Saad from Beirut.

Video of the funeral showed Iran’s supreme leader, Ayatollah Ali Khamenei, and its new president, Masoud Pezeshkian, wiping away tears during prayers for Mr. Haniyeh. Although Iran supports Hamas in the nearly 10-month war against Israel, Mr. Haniyeh’s funeral displayed an unusual outpouring of emotion by leaders of the Shiite government for a Sunni militant.

In a social media post after the funeral, Iran’s government said Mr. Pezeshkian had called an unnamed Hamas official in the organization’s political office to convey that “Iran has not failed to support the oppressed Palestinians and continues to support the resistance with a firmer determination.”

Additionally, the Iranian foreign minister, Ali Bagheri, called Egypt’s top diplomat to press for an emergency meeting of the Organization of Islamic Cooperation, demanding “all regional Muslim states to take a measure in order to counter the terrorist aggression,” according to a government statement.

Iran and Hamas blame Israel for killing Mr. Haniyeh, who had been in Tehran to attend Mr. Pezeshkian’s inauguration. American officials have also assessed that Israel was responsible for the attack, although Israel has not publicly acknowledged that.

In contrast, Israel was quick to describe a strike it launched in Lebanon on Tuesday night, killing a senior Hezbollah official, hours before Mr. Haniyeh was assassinated with an explosive device nearly 1,000 miles away. The funeral for the Hezbollah official, Fuad Shukr, was also held on Thursday.

The strikes, and pledges of retaliation by Iran and its allies, have raised concerns among Western officials about a wider regional war.

During prayers for Mr. Haniyeh in Tehran, Mr. Khamenei appeared to repeatedly look up and scan the sky, prompting social media speculation that he was worried about being targeted during the funeral.

The tension in the region intensified on Wednesday morning, when Hamas and Iran accused Israel of assassinating Ismail Haniyeh, one of the most senior Hamas leaders. Israel has not addressed the killing.

“There’s no doubt that an attack by Hezbollah, which knows and is capable of operating abroad, should increase the level of security provided to the delegation,” Shmulik Philosof, a former head of a Shin Bet unit that was responsible for securing Israeli delegations, said of the Israeli team now competing in the summer Olympics.

Concerns for the Israeli team — which has been shrouded in protection at every Games since 11 of its athletes and coaches were killed at the Munich Olympics in 1972 — have substantially increased since the Oct. 7 terrorist attacks, the subsequent war in Gaza, global protests and continuing threats.

Before traveling to Paris, Israeli athletes reported receiving anonymous emails that threatened, “we intend to repeat the events of Munich 1972.”

Mark Adams, a spokesman for the International Olympic Committee, would not comment on whether security had been augmented Wednesday for the Israeli team. “Rest assured there is very good, very strong security,” he said.

The French authorities have dedicated a special team to protect the Israeli delegation, according to Mr. Philosof, as host countries have done in previous Olympics. But, he added, “our policy is not to rely solely on local security anywhere, ever.”

Israel is one of the few nations that rely on its own security operation to supplement the security provided by the Olympic host country. Shin Bet, Israel’s domestic security agency, spent two years preparing the plan for the Paris Olympics, a process that included numerous meetings between agency officials and their French counterparts, according to two former Shin Bet senior officers. In early June, Israel’s culture and sports minister, Miki Zohar, said the delegation’s security budget had increased by 50 percent.

Israeli athletes had already been preparing for an abnormal Olympic experience. They expected their time at the Games to be marked as much by protests, heavy security, intense scrutiny and questions around politics and the war raging in Gaza as their own competitions.

“It’s a bummer, but it is what it is,” Maor Tiyouri, an Israeli marathoner, said before she arrived in Paris.

Ms. Tiyouri, who also ran the marathon at the Tokyo Olympics three years ago, has competed internationally since she was 16. Now 33, she doesn’t wear any national gear when she travels, she said, and has taped over the Israeli flag on her national team backpack.

“It’s always been this way,” Ms. Tiyouri, said, adding, “It’s hard but that’s just the reality of things, and if that means I’m more safe, then that’s what I’m going to do.”

It’s not so different for Anat Lelior, an Israeli surfer, who has reached the round of 16 in the women’s event. Representing Israel is “nowadays a lot different,” she said from Teahupo’o, Tahiti, where the surfing competition is being held. “I don’t go around saying I’m Israeli as much as I have, just for my safety.”

Israeli athletes have been instructed to not engage in protests or discussions, or to share their own opinions about the war, regardless of what they may be. Being asked to censor themselves is exhausting yet expected, many say. The athletes said they felt that to many, they were a flag — not a person or athlete with their own beliefs or political views but a repository for anger or frustration.

There have been some strained interactions among athletes. Adam Maraana, a 100-meter backstroke swimmer and the first Israeli-Arab to represent Israel since 1976, tried to swap pins with Algerian athletes but was turned away, he said. (Pin trading is a tradition at the Olympic Games. Countries, sports and brands make special Olympic pins, and athletes flash their finds along their identification lanyards.)

“I do understand it’s their choice, but it’s a little bit disappointing,” Maraana said.

Still, athletes are clinging to the joy of participating in the Olympics.

Itamar Einhorn, a soft-spoken Israeli cyclist competing in his first Olympics, has worked to balance the emotions and complexities that come with representing Israel with the fulfillment of a childhood dream.

News back home affects him a lot of the time. But, he said, with a sigh, “This is a very special experience.”

He has been revered within some Palestinian circles for overseeing the development of Hamas’s military abilities and has been a symbol of the group’s resilience, finding ways to survive despite being a top target of one of the most powerful militaries in the Middle East.

On Oct. 7, as Hamas launched an attack on Israeli towns and military installations, Mr. Deif released a recorded speech declaring that the group had launched its operation so “the enemy will understand that the time of their rampaging without accountability has ended.”

“Righteous fighters, this is your day to bury this criminal enemy,” he said in the speech, which was broadcast on Hamas’s Al-Aqsa TV. “Its time has finished. Kill them wherever you find them,” he added. “Remove this filth from your land and your sacred places. Fight and the angels fight with you.”

Hamas is backed by Iran, and Mr. Deif has supported the relationship.

He has not been seen publicly in years, and few photographs of him are in the public domain. In January, the Israeli Army published an image of a man it said was Mr. Deif; the picture showed him resting under a tree with a wad of cash in hand.

He is believed to have been disabled, possibly missing an eye and limbs. Israel bombed his home in 2014, killing his wife and infant son.

In May, Karim Khan, the International Criminal Court’s prosecutor, requested an arrest warrant for Mr. Deif, accusing him and two other Hamas leaders of war crimes and crimes against humanity. Hamas rejected the prosecutor’s claims.

Mr. Deif was born in 1965 to a poor Palestinian family and grew up in the Khan Younis refugee camp near Yahya Sinwar, the leader of Hamas in Gaza, and Mohammed Dahlan, an exiled leader of Fatah, another Palestinian faction that rivals Hamas.

Ibrahim Madhoun, an analyst close to Hamas, said of Mr. Deif in an interview: “His fingerprints are on the transformation of the Qassam Brigades from a limited number of armed cells to a formal army that has tens of thousands of fighters.”

Mr. Deif commanded the so-called Shadow Brigade, which guards Israeli captives held by Hamas, and invested significantly in manufacturing weapons and bringing new technologies to the Qassam Brigades such as reconnaissance drones, Mr. Madhoun said.

“Following an intelligence assessment, it can be confirmed that Muhammad Deif was eliminated in the strike,” the Israeli military statement said, without offering any more specific evidence that he was dead.

At least 90 people on the ground in the vicinity of the strike were killed that day, according to the Gazan health ministry. Its tally does not distinguish between civilians and combatants, but health officials said some were women and children.

Mr. Deif, who survived several previous Israeli assassination attempts, has been the No. 2 Hamas leader inside Gaza. He is the highest-ranking Hamas figure inside Gaza that Israel says it has killed since Oct. 7.

Israel’s government made eliminating Hamas’s leadership a stated goal of the war, and Mr. Deif’s death would be counted as a victory in that effort. How Hamas’s operations could be affected remains to be seen, though: Israel has killed many senior commanders in the past, only to see the group swiftly replace them.

The announcement came a day after the assassination of Ismail Haniyeh, the Qatar-based leader of Hamas’s political bureau. He was killed in an explosion in the Iranian capital, Tehran. Both Hamas and Iran blamed Israel, which has not confirmed or denied its involvement.

Mr. Deif has been de facto second in command to the group’s leader inside Gaza, Yahya Sinwar.

Born in 1965 to a poor Palestinian family, Mr. Deif grew up in the Khan Younis refugee camp and joined Hamas as a young man, around the time the group was founded in the late 1980s.

He quickly rose through the organization’s ranks, developed a reputation as a master bomb maker and orchestrated a number of attacks on Israel, including a series of deadly bus bombings that undermined the Israeli-Palestinian peace process in the mid-1990s.

Analysts credit him with transforming Hamas’s military wing, the Qassam Brigades, into a powerful and well-organized fighting force with tens of thousands in its ranks.

Mr. Deif’s success at escaping previous Israeli efforts to kill him — he was believed to have lost an eye and been seriously wounded — only enhanced his status in the eyes of some Palestinian admirers.

He survived more than eight attempts on his life, according to Israeli intelligence. In 2014, an Israeli airstrike killed one of his wives and at least one of his children, an infant son. In a brief 2021 conflict in Gaza, Israel’s military said it had tried to kill him several times.

When the Oct. 7 attack on Israel was underway, Mr. Deif released a recorded speech saying that Hamas had launched the assault so that “the enemy will understand that the time of their rampaging without accountability has ended.”

Since October, Israel has again had Mr. Deif in its cross hairs, killing his deputy, Marwan Issa, in March.

In May, Karim Khan, the International Criminal Court’s chief prosecutor, requested a warrant for Mr. Deif’s arrest, accusing him and two other Hamas leaders of war crimes and crimes against humanity. The prosecutor also sought arrest warrants for Israel’s prime minister, Benjamin Netanyahu, and its defense minister, Yoav Gallant.

Hamas criticized Mr. Khan for seeking to prosecute its leaders alongside Israeli officials, which it deemed “equating between the executioner and the victim.”

Mr. Deif spent decades underground in the tunnel network that typically shields Hamas leaders, according to Israeli intelligence officials, and had not been seen publicly in years. But officials recently said the Israeli military believed that he had developed health problems that forced him to spend more time above ground.

The strike that the Israeli military said killed him was authorized after prolonged surveillance of a house in southern Gaza where another top Hamas lieutenant, Rafa Salameh, was believed to be staying with his family, according to Israeli officials.

After learning that Mr. Deif appeared to be at the location, Israeli fighter jets struck with at least five precision-guided bombs, the officials said. Israel has said Mr. Salameh was also killed, a claim Hamas has not directly addressed.

That evening, Mr. Netanyahu said that an airstrike had targeted Mr. Deif but that there was not yet “absolute certainty” as to whether he had been killed.

“His hands are steeped in the blood of many Israelis,” Mr. Netanyahu said. “At the beginning of the campaign, I laid down a rule: The Hamas murderers are dead men, from the first to the last.”

Cassandra Vinograd and Rawan Sheikh Ahmad contributed reporting.

The official who shared the image spoke on the condition of anonymity because he was not authorized to speak publicly. The photo, which is circulating on Telegram channels affiliated with Iran’s Revolutionary Guards, shows a six-story structure in the upscale, leafy neighborhood of Zafaranieh in northern Tehran. The building is adjacent to the Saadabad Palace, which is used for government ceremonies. Its location is consistent with early reports of an explosion in northern Tehran, and The Times matched the building visible in the photo with satellite imagery of the site, confirming it is a building at the northern edge of Tehran.

One corner of the building appears to have sustained damage and is covered with a green cloth. Rubble can be seen on the roof of the first floor.

Just six days ago, another image of the same building, taken by the satellite company Maxar Technologies on July 25, shows no visible damage and no green tarp. That suggested that the image showing damage was taken more recently. It was not clear exactly when the tarp was placed on the building.

“The assassination of Ismail and Rami, while they were documenting the crimes of Israeli forces, underscores the urgent need for immediate legal action against the occupation forces to ensure that there is no impunity,” Al Jazeera Media Network said in a statement.

Mohammed Moawad, Al Jazeera’s managing editor, praised Mr. al-Ghoul’s courage in a post on social media.

“Ismail was renowned for his professionalism and dedication, bringing the world’s attention to the suffering and atrocities committed in Gaza,” he said.

The Committee to Protect Journalists has said the war in Gaza has led to the deadliest period for correspondents since it began gathering data in 1992, with at least 111 journalists and media workers among the more than 39,000 people killed in Gaza.

Mr. Moawad posted a message that he said had been written by Mr. al-Ghoul, in which the journalist reflected on being haunted by the incessant civilian suffering and death he’d seen while reporting on the conflict in Gaza.

“Let me tell you, my friend, that I no longer know the taste of sleep,” Mr. al-Ghoul wrote. “The bodies of children and the screams of the injured and their blood-soaked images never leave my sight. The cries of mothers and the wailing of men who are missing their loved ones never fade from my hearing.”

He added: “I am tired, my friend.”

An Al Jazeera video from outside a hospital showed two corpses on stretchers wearing vests meant to protect journalists, marked with the word “press.” The journalists were on their way to a hospital after being asked to leave the area by Israeli forces, according to Al Jazeera.

Jodie Ginsberg, the chief executive of the Committee to Protect Journalists, said in a statement on social media that the organization was “dismayed” by the journalists’ deaths.

“Journalists are civilians and should never be targeted,” she said. “Israel must explain why two more Al Jazeera journalists have been killed in what appears to be a direct strike.”

The Israeli military did not immediately respond to a request for comment on Wednesday.

Israel has a fraught relationship with Al Jazeera. In May, the Israeli government shut down the organization’s local operations in a step that critics denounced as anti-democratic and part of a broader crackdown on dissent over the war against Hamas.

Prime Minister Benjamin Netanyahu has accused Al Jazeera, a major source of news in the Arab world that has often highlighted civilian suffering in Gaza, of harming Israel’s security and inciting violence against its soldiers, though Israeli officials offered no examples. The initial order to shut down, set for 45 days, has since been extended.

The New York Times and other major international outlets have evacuated Palestinian journalists who had been working for them in Gaza. Israel and Egypt have restricted entry by international journalists into Gaza — with the exception of coordinated visits to specific sites with the Israeli military — so the stories that emerge from the war have often been left to local Palestinian reporters to document alone, working in extremely dangerous conditions.

“It is clear that journalists need to be protected,” Stéphane Dujarric, a United Nations spokesman, told reporters in a briefing on Wednesday. “These and other similar incidents must be fully and transparently investigated, and there must be accountability.”

Anushka Patil contributed reporting.