Israel believes that more than a third of the remaining Gaza hostages are dead, a government tally showed on Tuesday, as the United States sought to advance their recovery under a proposal to wind down the war with Hamas.

Of about 250 people dragged into the Gaza Strip by Hamas-led Palestinian gunmen during the Oct. 7 cross-border rampage that sparked the war, scores were freed in a November truce, while others have been recovered - dead or alive - by Israeli troops.

The government tally said 120 remain in captivity, 43 of whom have been declared dead in absentia by Israeli officials based on various sources of information, including intelligence tip-offs, CCTV or bystander videos and forensic analysis.

Some officials have privately said that the number of dead could be higher.

Hamas, which threatened at the outset of the war to execute hostages in reprisal for Israeli air strikes, has since said such attacks caused hostage deaths. Israel has not ruled that out in all cases, but said that some recovered hostage bodies showed signs of execution.

On Monday, four more hostages were added to Israel's list of fatalities.

U.S. President Joe Biden on Friday went public with an Israeli proposal to wind down the war, under which some hostages would go free during a preliminary ceasefire.

But mediated efforts to clinch that deal have been bogged down as Israel insists on eventually resuming the campaign to destroy Hamas while the Palestinian Islamist group demands a guaranteed end to the war and withdrawal of all invasion forces.