Hamas said on Monday that 33 hostages in Gaza had been killed during the almost 14-month-old war between the Palestinian group and Israel in the enclave, without giving their nationalities.
Hamas added that other hostages had gone missing.
"With the continuation of your crazy war," it said in a statement addressed to Israel, "you could lose your hostages forever. Do what you have to do before it is too late."
Hamas shortly afterward published a video it said detailed when and how the hostages had been killed, blaming Israeli Prime Minister Benjamin Netanyahu for their fate.
Hamas detailed several incidents, including the deaths of four hostages and their captors on October 9 and nine others on October 14 of last year as a result of intensive Israeli bombing.
Another hostage was reported to have been killed on December 8, 2023, during an Israeli operation attempting to rescue a captive soldier, who died as a result.
The group also said that seven hostages were killed on March 1, 2024, after weeks of losing contact with their captors, while three others were killed in an Israeli massacre in Gaza on June 9, 2024.
The Israeli military did not immediately comment, which came as Israeli military strikes continued in Gaza.
Israel estimates that there are currently 101 Israeli prisoners held in Gaza.
Hamas has called for an end to the war and total Israeli withdrawal from Gaza as part of any deal to release remaining hostages. Netanyahu has said the war will go on until Hamas is eradicated and poses no more threat to Israel.
Israel launched its war after Hamas-led fighters attacked Israeli communities on October 7, 2023, killing 1,200 people and capturing more than 250 hostages, according to Israeli tallies.
Israel's military offensive has killed more than 44,400 Palestinians and displaced most of Gaza's population, Gaza officials say. Vast swathes of the enclave lie in ruins.