When the four Israelis woke up in Gaza City on Saturday, they had been held hostage by Hamas for 245 days. The buildings in which they were being kept, two low-rise, concrete apartment blocks, looked much like the other nearby residences in a civilian neighborhood full of Palestinian families.

Within a few hours, the captives, three men and one woman, would be reunited with their own families, the result of a risky, long-planned rescue operation in which the full might of the Israeli military would be used to devastating effect.

“I’m so emotional,” one hostage, Noa Argamani, 26, told Israeli Prime Minister Benjamin Netanyahu in a phone call after her release. “It’s been so long since I heard Hebrew.”

The rescue effort involved hundreds of intelligence officers and two teams of commandos who simultaneously stormed the homes in which the hostages were being held, the Israeli military said.

In one apartment, where the male hostages were imprisoned, a firefight broke out between the soldiers and the Hamas guards, according to the military and video footage it released of the encounter. Later, and under a hail of gunfire, the truck in which three hostages and a wounded Israeli officer were being evacuated broke down and was surrounded by militants, Israeli officials said.

In an effort to give the rescuers enough time and ample cover to get the captives to freedom, the military said, the air force began striking dozens of nearby targets. Many Palestinians became aware of the fighting only when they heard bombs exploding.

Scores of local people, including children, were killed during the rescue operation. The health authorities in the Hamas-controlled territory put the number at more than 270. The Israeli military said the figure was fewer than 100. Neither the Israeli military nor Palestinian health officials provided a breakdown of civilians and combatants killed in the raid.

The Lead-Up

Weeks before the raid, Israeli intelligence officials identified two buildings, about 600 feet apart, in which they believed the hostages were being held.

In May, Israeli intelligence officials determined that Argamani — whose capture from a music festival by militants on Oct. 7 was caught on widely shared video — was being held in a family’s apartment near the Nuseirat market, Rear Adm. Daniel Hagari, the Israeli military’s chief spokesperson, told reporters. Nearby, in the apartment of another family were the three male hostages: Almog Meir Jan, 22, Andrey Kozlov, 27, and Shlomi Ziv, 41.

The home in which the men were held belonged to Abdallah Aljamal, according to the Israeli military. Aljamal’s death was confirmed by the Gaza Strip’s Government Media Office on Sunday, which said he had worked for the Hamas-affiliated news agency Palestine Now.

“We decided to conduct the operation on both apartments because if we would have chosen only one of them, the risk that the terrorists would kill the hostages in the other one would have been too high,” Hagari said.

In preparation for the mission, the military “built models of these houses in order to practice,” Hagari said, adding that the coordination between the two teams had to be “as precise as a brain operation” lest a mistake in one group lead to problems for the other.

The Raid

On Saturday morning, as the sun approached its blazing midday zenith, the residents of Nuseirat left the heat of their apartment buildings. Outside, they went to work, shopped at the market and visited family.

“It was so normal and the streets were full of life, people selling and buying things,” said Bayan Khaled abu Amr, 32, who had left home that morning to visit her uncle.

Fifty miles away, Israeli officers crowded into the Tel Aviv command room of Shin Bet, the Israeli security agency. “The tension in the air,” Hagari said, was “very, very high.”

There, around 11 a.m., Gen. Herzi Halevi, the military’s chief of the general staff, uttered the word “Go,” authorizing commandos in Israel’s YAMAM counterterrorism unit to begin the raid.

Soldiers in the unit started up two vehicles that had the appearance of local trucks, Israeli officials said, and made their way to each of the buildings where the hostages were being held.

Khalil abdul Qader al-Tahrawi, a 60-year-old shop owner, said he was sitting outside his store when he saw people dressed in the uniforms of the Qassam Brigades, the militant wing of Hamas, approach the building in which the three men were later found being held.

The group, he said, struck him as “suspicious and strange,” not least because they “climbed up the building with ladders and went down again pointing their guns everywhere.” He said he believed they were Israeli commandos.

Other witnesses described men they, too, believed were Israeli special forces operators, but dressed in civilian clothes.

Israeli officials declined to say whether Israeli forces had worn disguises during the raid.

Moments after Halevi authorized the operation, troops simultaneously raided both buildings. Argamani was kept under guard in a locked room, and her captors were quickly killed before they even realized what was happening, Israeli officials said.

“In Noa Argamani’s building,” Hagari said, “our forces surprised them completely.”

The Escape

Around the time the team assigned to free Argamani was driving her to a helicopter extraction point along Gaza’s Mediterranean coast, the team working to rescue the three men in the other building began taking fire, Hagari said.

It was then that Arnon Zmora, 36, an officer in the YAMAM unit, was shot and wounded, according to Hagari. Body-cam footage released by the Israeli border police shows Israeli troops finding the male hostages inside a residential apartment building, even as they continued to exchange fire with militants off screen.

In the footage, edited to blur soldiers’ faces and remove images of gore, the hostages are then seen leaving the building and scrambling through a tree-filled lot as gunfire erupts all around them.

“Members of Hamas shot at them,” said al-Tahrawi, the shop owner.

More militants joined the fight, according to Hagari, “running in the streets with RPGs,” an acronym for rocket-propelled grenades. “A lot of fire was around us,” he said.

As Argamani was approaching the beach in one vehicle, the other truck being used in the rescue broke down, according to Israeli officials, who requested anonymity to discuss a clandestine operation. To provide the stalled truck with cover, the officials said, the air force began bombing the nearby area, effectively creating a shield of fire.

“Suddenly, I heard a loud bomb and sound of some missiles around that mosque,” said abu Amr, the woman who had been out visiting her uncle. “I cannot remember the exact time, but maybe 11:20 a.m.”

“Again, a big, loud missile was heard, and gray smoke was rising,” abu Amr added. “People started shouting.” In the chaos of the bombing, she said, “kids were screaming; women were falling down while running.”

Israeli ground forces stationed nearby made their way to the disabled truck and transferred the hostages and Zmora, the wounded officer, to another vehicle, Israeli officials said.

From there, they sped to the beach, where the second of two helicopters had been waiting for them. The first had already taken off with Argamani on board.

Footage released by the military showed soldiers walking the hostages along the beach as a helicopter whipped up clouds of sand.

The Aftermath

“We called the hostages diamonds, so we say we have the diamonds in our hands,” Hagari said.

Zmora was evacuated to an Israeli hospital, where he later died of his wounds.

On Sunday, the corridors and hallways of the last major medical center in central Gaza, Al-Aqsa Martyrs Hospital in Deir al-Balah, remained “densely crowded” with new patients, after more than 100 bodies had been brought there Saturday, said Khalil Daqran, a hospital official. Most of the bodies have since been buried or claimed by relatives, he added.

The New York Times News Service