Israeli forces recovered the bodies of six Israeli hostages from southern Gaza in an overnight operation, the Israeli military said on Tuesday, highlighting the plight of the scores of captives remaining in the Palestinian enclave.

The military named the hostages whose bodies were returned to Israel as Yagev Buchshtab, Alexander Dancyg, Avraham Munder, Yoram Metzger, Nadav Popplewell and Haim Peri. All but Mr. Munder were already known to have lost their lives in captivity.

They were among about 250 people taken hostage last Oct. 7, when Hamas-led militants crossed into Israel from Gaza and carried out attacks that killed about 1,200 people, according to Israeli authorities.

Israeli forces have so far rescued only seven hostages alive. Scores more, mostly women and children, were returned to Israel during a weeklong cease-fire last November. More than 100 captives still remain in Gaza, at least 30 of whom are believed to be dead.

Israel’s defense minister, Yoav Gallant, said that the six bodies had been retrieved from Hamas tunnels beneath the city of Khan Younis in a “complex operation.”

The circumstances of the deaths of the six hostages were not immediately clear. A spokesman for Hamas’s military wing, Abu Ubaida, said in March that Mr. Metzger and Mr. Peri were among seven hostages who had been killed in Israeli airstrikes in Gaza. Hamas then said in May that Mr. Popplewell had died from injuries sustained in an Israeli airstrike more than a month before.

Weeks later, the Israeli military said that it was examining the possibility that the three hostages had been killed while Israeli forces were operating in the Khan Younis area.

The retrieval of the bodies came as Secretary of State Antony J. Blinken continued a diplomatic push in the region for a cease-fire deal that would see hostages released in exchange for Palestinian prisoners held in Israel. Frustration has grown in Israel over the months of halting negotiations, and family members of the hostages still in Gaza have led regular protests demanding a deal to secure their freedom.

Mati Dancyg, Alex Dancyg’s son, said he believed there had been opportunities to get his father out of Gaza alive. He accused Prime Minister Benjamin Netanyahu of putting political considerations first because key members of his governing coalition oppose a cease-fire deal, considering it a surrender to Hamas.

“It is absolutely clear to me that it was possible to bring him back home,” Mati Dancyg said Tuesday on Kan, Israel’s public radio network, adding, “Netanyahu chose to sacrifice the hostages.’’

Mr. Netanyahu has blamed Hamas for obstructing a deal. Mr. Netanyahu’s critics in Israel, as well as Hamas officials, say that Mr. Netanyahu recently added new conditions to a proposal outlined by President Biden in late May, adding to the difficulty of finalizing a deal.

“Our hearts grieve over the terrible loss,” Mr. Netanyahu said in a statement on Tuesday following the military’s announcement about the retrieval of the bodies. “The State of Israel will continue to make every effort to return all of our hostages — the living and the deceased.”

Mr. Munder, 79, Mr. Peri, 80, Mr. Metzger, 80, and Mr. Dancyg, 75, were all abducted alive on Oct. 7 from Nir Oz, a kibbutz, or communal village, near the Gaza border. Mr. Popplewell, 51, and Mr. Buchshtab, 35, were taken from another border community, Nirim.

The Hostages Families Forum, an organization that represents many of the hostages’ relatives, said in a statement on Tuesday that “Israel has a moral and ethical obligation to return all the murdered for dignified burial and to bring all living hostages home for rehabilitation.”

“The immediate return of the remaining 109 hostages,” it added, “can only be achieved through a negotiated deal.”