The military claimed all six had been killed shortly before they were to be rescued by Israeli forces.

Their recovery sparked calls for mass protests against Prime Minister Benjamin Netanyahu, who many families of captives and much of the wider Israeli public blame for failing to bring them back alive in a deal with Hamas to end the 10-month-old war.

Negotiations over such a deal have dragged on for months.

Militants seized Hersh Goldberg-Polin, 23, and four of the other captives at a music festival in southern Israel during Hamas' Oct. 7 operation.

The native of Berkeley, California, lost part of his left arm to a grenade in the attack. In April, a Hamas-issued video showed him, his left hand missing and clearly speaking under duress, sparking new protests in Israel urging the government to do more to secure his and others’ freedom.

The army identified the other captives as Ori Danino, 25; Eden Yerushalmi, 24; Almog Sarusi, 27; and Alexander Lobanov, 33; who were also taken from the music festival. The sixth, Carmel Gat, 40, was captured from the nearby farming community of Be'eri.

It said the bodies were recovered from a tunnel in the southern Gaza city of Rafah, around a kilometer (0.6 mile) from where another captive, Qaid Farhan Alkadi, 52, was rescued alive last week.

Rear Adm. Daniel Hagari, the Israeli military spokesperson accused Hamas of killing the four captives shortly before the army reached them.

There was no immediate comment from Hamas.

Netanyahu has taken a tough line in negotiations and repeatedly said that military pressure is needed to bring home the captives. According to Israeli media, he has feuded with top security officials who have said a deal should be reached urgently.

Hamas has offered to release the captives in return for an end to the war, the withdrawal of Israeli forces and the release of a large number of Palestinian prisoners.

A forum of captive families called for a massive protest on Sunday, demanding a “complete halt of the country” to push for the implementation of a cease-fire and captives release.

“A deal for the return of the hostages has been on the table for over two months. Were it not for the delays, sabotage, and excuses those whose deaths we learned about this morning would likely still be alive. It’s time to bring our hostages home,” it said in a statement.

President Joe Biden, who had met with the parents, said he was “devastated and outraged.”

“It is as tragic as it is reprehensible,” he said. “Make no mistake, Hamas leaders will pay for these crimes. And we will keep working around the clock for a deal to secure the release of the remaining hostages.”

The Goldberg-Polin family issued a statement early Sunday, hours after the Israeli army said it had located bodies in Gaza.

“With broken hearts, the Goldberg-Polin family is devastated to announce the death of their beloved son and brother, Hersh,” it said.

Goldberg-Polin’s parents, U.S.-born immigrants to Israel, became perhaps the most high-profile relatives of captives on the international stage. They met with Biden, Pope Francis and others and addressed the United Nations, urging the release of all captives.

On Aug. 21, his parents addressed a hushed hall at the Democratic National Convention — after sustained applause and chants of “bring him home.”

Some 250 captives were taken on Oct. 7. Before the military’s announcement of the latest discovery of bodies, Israel said it believed 108 captives were still held in Gaza and about one-third of them were dead. In late August, the Israeli military recovered the bodies of six captives in southern Gaza.

Eight captives have been rescued by Israeli forces, the most recent found on Tuesday. More than 100 were freed during a weeklong cease-fire in November in exchange for the release of Palestinians imprisoned by Israel.

Two previous Israeli operations to free captives killed scores of Palestinians. Hamas says several captives have been killed in Israeli airstrikes and failed rescue attempts. Israeli troops mistakenly killed three Israelis who escaped captivity in December.