The Islamic group Hamas says five hostages it was holding are believed to have been killed in an Israeli attack.
Hamas's armed wing, the Al-Qassam Brigades, issued a statement saying it lost contact with the group responsible for the five hostages after a bombardment carried out by Israel.
The brigades say the five include three men aged from 79 to 84 who pleaded for their release in a video released on December 18.
An estimated 130 people are believed to remain captive in the Gaza Strip. Israeli military operations have so far successfully rescued only one person.
Meanwhile, health authorities in Gaza said on Saturday that the deaths of 201 people were confirmed over the past 24 hours.
They said that brought the total number of deaths in the enclave to 20,258 since the current conflict started on October 7.
Qatar-based satellite TV network Al Jazeera says emergency workers have returned to parts of northern Gaza, where fighting has subsided. Israeli forces say they will soon take full control of northern Gaza. The network says bodies that have been buried under the rubble, or temporarily left behind on roads, are being recovered.
Israeli forces have been intensifying their attacks on southern Gaza, where they believe Hamas leaders are hiding.
On Saturday, they claimed to have eliminated a senior Hamas official responsible for arms trade, production and procurement.
Video footage released by the military shows a vehicle being targeted and then destroyed by a fighter aircraft in a precision attack.