Last-minute talks to extend the Israel-Hamas truce have been overshadowed by a claim that a 10-month old Israeli hostage and his family had been killed by a strike in Gaza.

The ceasefire and hostage exchange deal is due to expire on Thursday (AEDT) after the sixth release of civilians, and negotiations are underway with mediators Egypt and Qatar.

Hamas is reportedly seeking a four-day extension and Israel has said it would hold its fire 24 hours for every 10 hostages released before resuming its campaign to annihilate Hamas.

But overshadowing the fragile deal, Hamas announced on Thursday (AEDT) that the youngest hostage – baby Kfir Bibas – had died in an earlier Israeli bombing. His four-year-old brother Ariel and their mother are also said to have died.

The children’s father has also been held.

The Israeli military said it was checking the “cruel and inhumane” claim, which was potentially explosive given the high-profile campaign in Israel to free the family.

Relatives had issued a special appeal for the family after they were not among civilians freed on Tuesday (local time).

Earlier the Israel Defence Forces (ADF) posted about the family on X, saying: “Hamas must be held accountable. Hamas must release all hostages immediately.

“Hamas is wholly responsible for the security of all hostages in the Gaza Strip,” the army said in a statement.

Tweet from @IDF

There are just hours left to reach a truce extension on Thursday (AEDT) when a six-day pause is due to expire.

Families of Israeli hostages have been informed of the names of the final group due to be released later in the day.

A Palestinian official told Reuters that despite a willingness on both sides to prolong the truce, no agreement had been reached.

Discussions were still underway with mediators Egypt and Qatar, the official said.

Israeli government spokesman Eylon Levy said Israel would consider any serious proposal.

“We are doing everything we can in order to get those hostages out. Nothing is confirmed until it is confirmed,” Levy said in Tel Aviv.

“We’re talking about very sensitive negotiations in which human lives hang in the balance.”

Once the release of hostages ended, the fighting would resume, he said.

“This war will end with the end of Hamas.”

Hostage confronted Hamas chief

An 85-year-old Israeli woman abducted by Hamas on October 7 and set free two weeks later says she met its Gaza leader Yahya Sinwar while in captivity and asked him how he was not ashamed for having acted violently against peace activists like herself.

Yocheved Lifshitz, 85, was taken from her Kibbutz Nir Oz home in Israel to Gaza.

She told the Israeli newspaper Davar she confronted Sinwar when he visited the hostages in a tunnel where Hamas was holding them captive.

“Sinwar was with us three to four days after we arrived,” Lifshitz told the Hebrew-language Davar newspaper.

“I asked him how he is not ashamed to do such a thing to people who all these years have supported peace.”

“He didn’t answer. He was silent,” she said.

Lifshitz is a peace activist who, together with her husband, helped sick Palestinians in Gaza get to hospital for years, her grandson told Reuters.

Her 83-year-old husband Oded was also kidnapped from their home. He remains in captivity.

Following her release from Hamas captivity last month, Lifshitz said she “went through hell” during her two weeks as a hostage in the Gaza Strip.

Lifshitz was one of four women freed by Hamas early in the war.

She said she had been beaten when she was abducted but was then treated well during her two-week captivity. On her release, she turned to shake the hand of a masked captor.

Asked why, she replied: “They treated us gently and met all our needs.”

-with AAP