JERUSALEM (AP) -- The family of Israeli-American hostage Hersh Goldberg-Polin announced the young man's death early Sunday, ending a relentless campaign by his parents to rescue him that included meetings with world leaders and an address to the Democratic convention last month.

Goldberg-Polin, 23, was seized by militants at a music festival in southern Israel on Oct. 7. 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.

Israel's announcement is bound to bring urgent new calls for Prime Minister Benjamin Netanyahu to reach a deal to bring home the remaining hostages. The Israeli leader has taken a tough line in negotiations and repeatedly said that military pressure is needed to bring home the hostages. According to Israeli media, he has feuded with top security officials who have said a deal should be reached urgently.

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 family issued its 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. "The family thanks you all for your love and support and asks for privacy at this time."

There was no immediate comment from the army, details on the exact circumstances of his death or identities of other bodies recovered. But Biden said a total of six bodies had been recovered in a tunnel in the southern Gaza city of Rafah.

"I have gotten to know his parents, Jon and Rachel. They have been courageous, wise and steadfast, even as they have endured the unimaginable," he said. "They have been relentless and irrepressible champions of their son and of all the hostages held in unconscionable conditions. I admire them and grieve with them more deeply than words can express."

Israeli media began announcing the names of other hostages recovered in the operation, but the reports were not immediately confirmed. The army was set to issue an official statement later Sunday.

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

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

"This is a political convention. But needing our only son -- and all of the cherished hostages -- home is not a political issue. It is a humanitarian issue," said his father, Jon Polin. His mother Rachel, who bowed her head during the ovation and touched her chest, said, "Hersh, if you can hear us, we love you, stay strong, survive."

Both wore stickers with the number 320, representing the number of days their son had been held. It had long become part of a morning ritual -- tear a new piece of tape, write down another day.

"I find it so remarkable how nauseating it is every single time,'' Rachel Goldberg-Polin said in January, ahead of the 100-day mark. "And it's good. I don't want to get used to it. I don't want anybody to get used to the fact that these people are missing.''

She asked other people around the world to take up the ritual, too, not only for her son, who moved to Israel with his family when he was 7, but for the other hostages and their families.