JERUSALEM — The Israeli military said Tuesday that it recovered the bodies of six hostages taken in Hamas’ October 7 attack, as American and Arab mediators tried to advance an agreement to halt the fighting and release scores of other militant-held captives.

The military said its forces recovered the bodies in an overnight operation in southern Gaza, without saying when or how the six died. A forum for hostage families said they were kidnapped alive. Hamas says some captives have been killed and wounded in Israeli airstrikes.

The recovery is a blow to Hamas, which hopes to exchange hostages for Palestinian Arab prisoners, an Israeli withdrawal from Gaza, and a lasting cease-fire. It was also likely to increase pressure on Israel’s government to reach a deal to release dozens of hostages who are still believed to be alive.

The military said it had identified the remains of Chaim Perry, 80; Yoram Metzger, 80; Avraham Munder, 79; Alexander Dancyg, 76; Nadav Popplewell, 51; and Yagev Buchshtav, 35. Metzger, Munder, Popplewell and Buchshtav had family members who were also abducted but freed during a November cease-fire.

Munder’s death was confirmed on Tuesday by Kibbutz Nir Oz, the farming community where he was among around 80 residents who were taken captive. It said he died “after enduring months of physical and mental torture.” Israeli authorities had previously determined that the other five were deceased.

Prime Minister Netanyahu praised the recovery effort and said “our hearts ache for the terrible loss.” Israel, he said, “will continue to make every effort to return all of our hostages — both alive and dead,” he said in a statement.

Defense Minister Yoav Gallant also praised the operation, which he said had been carried out inside Hamas’ vast tunnel network. There were no immediate reports of any casualties among Israelis or Palestinians in the recovery operation.

Hamas is still believed to be holding around 110 hostages captured in the October 7 attack. Israeli authorities estimate around a third of them are dead.

Secretary Blinken, who is on his ninth visit to the region since the start of the war, said Monday that Mr. Netanyahu has accepted a proposal to bridge gaps in the cease-fire talks, which have dragged on for months, and called on Hamas to do the same. Mr. Blinken traveled to Egypt today and was also expected to hold talks in Qatar.