It comes after a document compiled by Israeli intelligence officers reported by the New York Times, suggested 32 have died since the Hamas attack inside Israel on 7 October and the Israeli bomardment of Gaza in response.
Four military sources, who spoke on condition of anonymity, said Israel was also assessing unconfirmed intelligence indicating that at least 20 other hostages may have also been killed, the paper reported.
The circumstances of the hostage deaths remains unclear with the Israeli authorities suggesting that many of those deaths had occurred during Hamas’s deadly attack, in which 1,200 people were killed and at least another 240 taken hostage.
The Israeli military told the New York Times that it was “deploying all available resources to locate and retrieve as much information as possible regarding the hostages currently held by Hamas.”
The US secretary of state, Antony Blinken, met officials in Egypt and Qatar on Tuesday during his fifth trip to the Middle East since October, as the three countries seek a hostage release deal and the war’s first extended truce. More than 100 captives, mostly women and children, were released during a weeklong ceasefire in November in exchange for the release of 240 Palestinians held in Israeli prisons.
The US’s top diplomat began the day in Saudi Arabia before jetting first to Cairo and then Doha to meet the rulers of Egypt and Qatar, mediators in talks that conveyed a truce offer to Hamas last week.
Israel, which is pressing on with its offensive deep into parts of the Gaza Strip now sheltering hundreds of thousands of people displaced from earlier fighting, said its forces had killed dozens of Palestinian gunmen in the past 24 hours.
Palestinians hope Mr Blinken’s talks will nail down a ceasefire before Israeli forces storm Rafah, where more than half of Gaza’s 2.3 million people are sheltering, mainly in public buildings and tents made from sheets of plastic, hard against the border with Egypt.
Mr Blinken met Egyptian president Abdel Fatah al-Sisi in Cairo and Qatari Prime Minister Sheikh Tamim bin Hamad Al Thani in Doha. Mr Blinken is set to meet Israeli leaders and the Western-backed Palestinian Authority on Wednesday.
The deal, drawn up more than a week ago by US and Israeli spy chiefs at a meeting with the Egyptians and Qataris, would secure the release of remaining hostages held by militants in Gaza in return for a long pause to fighting. Hamas says it must produce a definitive end to the war. Israel says it will not halt the war permanently until Hamas is destroyed.
Additional reporting by agencies