At the same time, Mr. Khan requested warrants for Prime Minister Benjamin Netanyahu of Israel and his defense minister, Yoav Gallant, because he said there was reason to believe that they also bore responsibility for war crimes and crimes against humanity, including using the starvation as a weapon of war against civilians and directing attacks against civilians.

The Hague-based court, which was formed by international treaty in 1998 to prosecute war crimes and genocide, had not announced whether it would approve the warrants before all three Hamas figures were killed.

Israeli military leaders said that Mr. Deif was killed in an airstrike in July in Gaza, which local health authorities said killed at least 90 other people. Weeks later, Mr. Haniyeh died when a bomb exploded in the guesthouse in which he was staying to attend a funeral in the Iranian capital, Tehran.

Israel said on Thursday that Mr. Sinwar, the political leader of Hamas and its most senior figure, had been killed in Gaza the previous day.

In August, Mr. Khan withdrew his request for the warrant for Mr. Haniyeh, citing his death. Legal experts said then that he was likely to also withdraw his warrant request for Mr. Deif, who at that point was believed but not confirmed to be dead. Mr. Khan may now withdraw his warrant request for Mr. Sinwar.

It was not immediately clear whether the deaths would have any impact on the court’s decision on the outstanding arrest warrant requests for Mr. Netanyahu and Mr. Gallant. If the court does issue the warrants, member states could be required to arrest the Israeli officials on entry into their territories.

Senior officials in Israel — which like the United States, China, India and Russia is not a member state of the court — have called the requests involving Mr. Netanyahu and Mr. Gallant outrageous, saying the prosecutor was equating them with the leaders of Hamas. Last month, the Israeli attorney general’s office filed documents to the court challenging its jurisdiction to issue the warrants on technical grounds.

The room seen in the drone video matches the location of earlier photographs obtained by The New York Times showing the corpse of a man closely resembling Mr. Sinwar. There is new damage to a wall of the room visible in the photographs, which indicates that an explosion occurred at some point after the drone footage. Also in the photos, the corpse is wearing a green kaffiyeh similar to the one worn by the man in the video.

The room is on the second floor of a residential building in the Tel al-Sultan neighborhood of Rafah in southern Gaza. Earlier on Thursday, the Israeli military released several videos of Israeli soldiers in the area after Mr. Sinwar was killed. The Times determined this footage was filmed near the same house in northern Rafah.

Israel’s military has recently expanded its operations in this neighborhood of Rafah. A video filmed in September showed soldiers going on a patrol in Rafah from a nearby military position. In the clip, the soldiers drive by the house in which Mr. Sinwar was later killed, although it is not clear whether he was in the building at the time the footage was filmed.

Since his release from an Israeli prison in 2011, and his subsequent ascent through Hamas’s ranks, Mr. Sinwar had been among the highest priority targets for Israel’s intelligence operation.

In 2021, during a brief war with Hamas, Israel bombed Mr. Sinwar’s home in an unsuccessful attempt to kill him. After that war ended, Mr. Sinwar announced on television that he was going to walk home and dared Israel to assassinate him. Then he strolled through the streets of Gaza, waving at shopkeepers and pausing for photos with admirers.

But Israel’s efforts to find Mr. Sinwar intensified significantly after the Hamas-led attacks on Israel on Oct. 7, 2023, which he helped to plan.

During a raid early in the war on a tunnel in Gaza City, in northern Gaza, Israeli soldiers found a video, filmed days earlier, of Mr. Sinwar moving his family to a different hiding spot under the city.

Israeli intelligence officials have said that they believe Mr. Sinwar, who married and had children after his release from prison, kept his family with him for at least the first six months of the war.

In January, Israeli and American officials said they thought that they had made progress toward finding him, when Israeli commandos raided an elaborate tunnel complex in southern Gaza based on intelligence that he might be hiding there.

But he had left the bunker, in the city of Khan Younis, just days earlier, leaving behind documents and stacks of Israeli shekels totaling about $1 million. After that, the trail appeared to go cold.

In the months that followed, Mr. Sinwar released no audio or video messages. Some Israeli officials said that, in the absence of signs of life, it was possible that he was dead.

He was not. Over the summer, his importance to negotiations over a cease-fire and the release of the hostages became clear, and Israeli and U.S. officials said that he was a significant impediment to a deal.

The assassination of the political leader of Hamas, Ismail Haniyeh, in July infuriated Mr. Sinwar, according to American officials. In August, Hamas named Mr. Sinwar as its political leader, bolstering his power within the group.

His power, which derived in part from his presence in Gaza, was difficult to exercise for largely the same reason that it was so difficult for Israel to locate him: He avoided almost all electronic communication tools.

Since the Oct. 7 attacks, Mr. Sinwar had avoided appearing in public, and he had not issued any audio or video messages in months, hoping to avoid giving away details that could lead to his capture or death.

Israeli forces, who have used communications between Hamas leaders to target them, appeared unable to identify exactly how Mr. Sinwar exchanged information with other Hamas officials.

Mr. Sinwar had stopped using electronic communications even before the war. Once it began, most experts had said that he lived full time in the network of tunnels that Hamas built beneath Gaza, and that he was most likely surrounded by hostages seized on Oct. 7 to reduce the chances that Israeli forces would attempt to kill him with an airstrike or a ground assault.

In September, an allied militant group in Lebanon, Hezbollah, released a letter from Mr. Sinwar thanking that group’s leader, Hassan Nasrallah, for supporting Hamas in its war with Israel. Hezbollah had begun cross-border exchanges of fire with Israel almost immediately after the war in Gaza began.

Some Hamas officials at the time suggested that the letter, which was not handwritten, had been written outside Gaza by someone else but with Mr. Sinwar’s approval.

It may prove to have been Mr. Sinwar’s last public communication, and it did little to help Mr. Nasrallah. Weeks later, Israel’s military assassinated him in an airstrike in Lebanon and then invaded Lebanon, aiming to drive Hezbollah away from its northern border.

Mr. Sinwar’s death was not unexpected, he was in Gaza and had been Israel’s top target since the beginning of the war. Perhaps because of that, his killing has not shaken Tehran as much as the assassination of Hamas’s political leader, Ismail Haniyeh, which took place in Tehran, or that of Hassan Nasrallah, the longtime leader of Hezbollah, another armed group also backed by Iran, in Beirut.

Iran’s mission to the United Nations said in a post on X that Mr. Sinwar would “become a model for the youth and children who will carry forward his path toward the liberation of Palestine. As long as occupation and aggression exist, resistance will endure, for the martyr remains alive and a source of inspiration.”

Iran’s president and foreign minister have not yet commented directly on the killing, likely waiting for Hamas to issue a statement of confirmation. But Gen. Mohammad Baqer Ghalibaf, the conservative speaker of Iran’s Parliament, at a speech in the city of Mashhad on Thursday, alluded to Mr. Sinwar when speaking of militant leaders killed by Israel.

“The martyrs of the Zionist regime’s crimes, especially martyr Sayyed Hassan Nasrallah, are all considered great treasures for Islamic movements and people. Their martyrdom does not mean the end of the resistance and the fight will continue,” said General Ghalibaf.

Supporters of Iran’s government posted messages of condolence and praise for Mr. Sinwar on social media. Hossein Kazeruni, a hard-line cleric, said on X that Mr. Sinwar died fighting Israel’s military “like a man, weapon in hand, wrapped in kaffiyeh, chest out.”

Official Iranian media was highlighting Mr. Sinwar’s close ties to Iran, including a video of him visiting Tehran in 2011 after his release from an Israeli prison and meeting with the supreme leader, Ayatollah Ali Khamenei, who told him, “With this spirit and mind-set, you will definitely be victorious.”

Reza Salehi, a conservative analyst in Tehran who is close to the government, said in an interview that the killing of Mr. Sinwar would not eradicate Hamas; rather, it would fuel more support for it. But he also said it would not prompt Iran to retaliate.

“Iran is not going to respond, but it is a significant event,” Mr. Salehi said. “In the short-term, Sinwar’s absence will affect Hamas’s field command and disrupt cease-fire negotiations.”

He added that Israel’s “aggressive onslaught” on Iran’s allies has already prompted a recalculation of Iran’s offensive and defensive strategies, meaning that Iran was departing from what it refers to as strategic patience to being more willing to take risks and strike back.

Iran has long funded, trained and provided weapons to Hamas and other Palestinian militants as part of the government’s ideology that Israel and Zionism must be eradicated and the lands returned to Palestinians. Iranian officials have repeatedly praised Mr. Sinwar as the architect of the Oct. 7 terrorist attacks on Israel, which Iran has described as “justified” and “a big victory.”

The news of Mr. Sinwar’s killing comes as Iran awaits Israel’s response to Iran’s missile attack earlier this month to avenge the killings of Mr. Nasrallah, Mr. Haniyeh and an Iranian senior commander.

Analysts in Iran said that it was unlikely that Mr. Sinwar’s killing would have a significant impact on Iran’s calculations of war with Israel. Iran wants to avoid an all-out war at the same time that it wants to establish deterrence against any potential widespread attacks by Israel on its infrastructure, nuclear sites and military bases. But Iran has warned it would strike back if they are attacked.

“Just to be crystal clear: This was an Israeli operation,” General Ryder said. “There was no U.S. forces directly involved.”

U.S. military personnel have helped the Israeli military locate other Hamas leaders, as well as hostages held in Gaza since the Oct. 7, 2023, attacks on southern Israel. But the Israeli operation that killed Mr. Sinwar, General Ryder said, was separate from the U.S. military’s continuing support.

Several other current and former senior U.S. military and defense officials concurred with General Ryder’s assertion that the United States did not play a role in the specific Israeli operation that killed Mr. Sinwar, which Israeli officials described as a chance encounter made by a unit of trainee squad commanders on patrol in southern Gaza on Wednesday that engaged Palestinian fighters in a firefight.

“It does sound like it was a routine patrol,” said Mick Mulroy, a former top Middle East policy official at the Pentagon and a retired C.I.A. officer. “If true, it shows the importance of these patrols.”

General Ryder also echoed remarks made by President Biden earlier in the day that the killing of Mr. Sinwar presented an opportunity to negotiate a cease-fire.

“Broadly speaking, we absolutely support a cease-fire so that we can ensure that humanitarian assistance is getting into Gaza, that the Palestinian people can see a restoration of security and stability,” General Ryder said. “But we also recognize the threat that Hamas has posed to Israel and so we’ll continue to consult with Israel and our partners in the region.”

He added: “Obviously we want to see a cease-fire as soon as possible, and most importantly the release of the hostages that continue to be held by Hamas.”

“Yahya Sinwar was an insurmountable obstacle to achieving all of those goals,” Mr. Biden said in a statement earlier on Thursday. “That obstacle no longer exists. But much work remains before us.”

The death of Mr. Sinwar, the Hamas leader who was the architect of the Oct. 7 attacks, comes as the relationship between Mr. Netanyahu and the U.S. president has frayed. The two leaders had spoken last week for the first time in two months to discuss Israel’s plans to retaliate against Iran for a missile attack earlier in October. Looming over that discussion was the burden of their worsening ties.

President Biden has on occasion privately expressed his frustrations with Mr. Netanyahu and his conduct of the war in Gaza, sometimes in salty terms, as documented in a new book by the investigative reporter Bob Woodward. Mr. Biden has also lamented to Mr. Netanyahu directly that he lacks a strategy for the war, according to the book.

But Mr. Sinwar’s death seems to present an opportunity for both men to claim a victory and perhaps get on the same page again. According to Mr. Netanyahu’s office, President Biden called him on Thursday evening and both leaders “agreed that there is an opportunity to advance a deal to free the hostages and they will work together to achieve that goal,” according to the Israeli statement.

Negotiations on a cease-fire deal that would see the release of the remaining hostages in Gaza have been deadlocked for months, with both Israel and Hamas blaming each other.

The unit was on patrol in southern Gaza on Wednesday when the Israeli soldiers came upon a small group of fighters, the officials said. The soldiers — backed by drones — engaged in a firefight, and three Palestinian militants were killed.

During the battle, Israeli fire brought down part of a building where the militants had taken cover, two officials said. As the dust cleared and they began searching the building, the Israeli soldiers noticed that one of the bodies bore a shocking resemblance to the Hamas leader, the three officials said.

It was a seemingly unlikely place to find him. Israeli and U.S. intelligence had long assessed that Mr. Sinwar — fearful for his own safety — had been hiding deep underground, surrounding himself with Israeli hostages to avoid assassination.

Photographs obtained by The New York Times, some of which later circulated online, show the body of a man with facial features strongly resembling Mr. Sinwar. The man’s body has several severe wounds, including to the head and leg. The photographs show that the body has several features matching those seen in archival footage of Mr. Sinwar, including distinctive moles near his eyes and crooked teeth.

Hours after the fight was over, the soldiers approached the bodies cautiously. The area was still littered with explosive devices, two officials said. They also thought that the body of one fighter, later identified as Mr. Sinwar, was booby-trapped.

They found money and weaponry alongside the militants, according to one of the officials, who shared photos of the scene, including some in which the items were on display.

The troops, one of the officials said, were also concerned that there might be hostages in the area as well, but none were found with the fighters. There is no evidence that any of the hostages still held in Gaza were harmed during the battle, the Israeli military said.

On Thursday evening, the Israeli military, after completing its identification process, announced that Mr. Sinwar was dead.

Aric Toler, Riley Mellen and Christiaan Triebert contributed reporting.

“I heard a lot of celebrations and cheers of joy in my neighborhood, and justifiably so,” Ms. Astmaker said, speaking by telephone from her home in Jerusalem soon after Mr. Sinwar’s death was confirmed. “But my head immediately filled with questions,” she added.

“What does it mean for Karina and the other hostages?” she said, raising the prospect of an accelerated push for a deal to bring them home or, more darkly, the possibility that Mr. Sinwar’s supporters could avenge his killing by harming them.

Mr. Sinwar, the leader of Hamas, was an architect of the Oct. 7 terror attack in Israel during which more than 1,200 people were killed and more than 250 others — civilians and soldiers — were captured and taken into Gaza, according to the Israeli authorities.

More than a hundred hostages were released in an initial deal last November during a temporary cease-fire in fighting after Israel had launched a punishing counteroffensive, and in exchange for the release of Palestinian prisoners and detainees from custody in Israel.

Of the 101 hostages remaining in Gaza, at least a third are believed to be no longer alive.

Only eight hostages have been rescued alive by Israeli forces. Others were taken into Gaza dead, have since been killed by their captors or, in some cases, were killed accidentally by Israeli fire.

Adding to the fears and sense of urgency over the fate of those remaining, six hostages were fatally shot at close range in late August by their captors in a tunnel in Rafah, in southern Gaza, apparently as Israeli soldiers, unaware of their presence, were operating nearby, aboveground, according to Israeli officials.

Negotiations for a new cease-fire deal that would bring about the hostages’ release have been at an impasse for some time.

Einav Zangauker, the mother of hostage Matan Zangauker and one of the most vocal and prominent campaigners for a hostage deal, said in a video statement, “Now, more than ever, the lives of my son Matan and the other hostages are in tangible danger.”

Ms. Zangauker, addressing Prime Minister Benjamin Netanyahu, implored the Israeli government to come up with a new diplomatic initiative. “Don’t bury the hostages,” she said, adding, “You have your victory image. Now bring a deal.”

Critics have accused Mr. Netanyahu of delaying a deal in recent months by adding new conditions. Mr. Netanyahu, in turn, blamed the failure on Mr. Sinwar.

In a televised statement announcing Mr. Sinwar’s death, Mr. Netanyahu addressed the families of the hostages, saying it was his, and the country’s, “supreme commitment” to bring them home. He called on all those holding the hostages to put down their weapons and give them up, promising that those who did so would be allowed to come out of hiding and live.

Ms. Astmaker said it was not clear to the families if the government knew where the hostages were, or what their situation was. The family of Ms. Ariev, the surveillance soldier, last received a sign that she was alive several months ago.

The Hostages Families Forum, a grass-roots group that supports the hostages’ families and advocates their release, commended the Israeli security forces for eliminating Mr. Sinwar, but also spoke to the precariousness of the moment.

“We express deep concern for the fate of the 101 men, women, elderly and children still held captive by Hamas in Gaza,” the group said in a statement.

Yehuda Cohen, the father of an abducted soldier, told Kan, Israel’s public broadcaster, that the death of Mr. Sinwar could have two very different outcomes for the hostages, echoing the concerns of Ms. Astmaker and Ms. Zangauker. It could help advance a process toward their release, he said. But he also said he was “fearful,” particularly after the killing of the six hostages in August.

“I hope no order has gone out,” he said, meaning an order for the gunmen holding the hostages to execute them should Mr. Sinwar be killed.

Carol Sutherland contributed reporting.

For months, Mr. Sinwar had evaded the sort of Israeli efforts to find and kill him that have led to the deaths of other senior officials in Hamas, including Mr. Haniyeh.

Hamas’s leadership structure is opaque, but here is what is known about some of Hamas’s most prominent figures who are still believed to be alive or whose fate is unclear:

Khaled Meshal, a former political head of Hamas

Born near the West Bank city of Ramallah, Mr. Meshal became the leader of Hamas’s political office in 1996, directing the group from exile. Two years later, Israeli agents injected him with a slow-acting poison in Jordan, sending him into a coma before he was saved by an antidote provided by Israel as part of a diplomatic deal with Jordan.

Mr. Meshal spent his career moving from one Arab nation to another, living in Kuwait, Jordan, Qatar and Syria. When he stepped down as head of the political office, he was succeeded in 2017 by Mr. Haniyeh. Mr. Meshal remains an influential official in the group.

Khalil al-Hayya, the deputy leader of Hamas in Gaza

Mr. al-Hayya, who now lives in exile in Qatar, has been a Hamas official for decades and is Mr. Sinwar’s deputy. He survived an Israeli assassination attempt in 2007, when an airstrike on his home in Gaza killed members of his family while he was not there.

Mousa Abu Marzouk, a member of Hamas’s top political bureau

One of Hamas’s founders, Mr. Abu Marzouk started his political career in the United Arab Emirates, where he helped found a branch of the Palestinian Muslim Brotherhood, from which Hamas was formed, according to the European Council on Foreign Relations.

He later went to the United States, where he helped found Islamic institutions, including those focused on the Palestinian cause. In 1996, when he headed Hamas’s political bureau, he faced Israeli charges of financing and helping organize terrorist attacks. After 22 months spent in a Manhattan jail on suspicion of terrorism, he agreed to relinquish his permanent resident status in the United States and said he would not contest the terrorism accusations that led to his detention. The United States then deported him to Jordan.

Muhammad Deif, the commander of Hamas’s military

Mr. Deif, another of the suspected planners of the Oct. 7 attacks, joined Hamas as a young man. In 2002, he became the leader of Hamas’s military wing, the Qassam Brigades, succeeding its founder, who was killed in an Israeli strike. Mr. Deif has since orchestrated multiple attacks on Israel, including a series of suicide bombings in 1996.

In July, Israeli forces bombarded a densely packed coastal area of Gaza with heavy munitions in an attempt to kill Mr. Deif. Scores of Gazans were killed in the attack. Israel’s military later said that it had killed Mr. Deif in the strike. Hamas has neither confirmed nor denied his death.

He had been at the top of Israel’s list of most-wanted terrorists for decades, earlier evading more than eight attempts on his life, according to Israeli intelligence. In 2014, an Israeli airstrike killed one of his wives and their infant son.