An Israeli group representing families of hostages held by Hamas says the remains of all four hostages returned early Thursday have been identified. Hamas says it is ready to negotiate the next phase of the cease-fire.

Israel has delayed the release of about 600 Palestinian prisoners since Saturday to protest what it says is the cruel treatment of hostages during their release by Hamas.

Israel and Hamas have reached an agreement to exchange the bodies of four hostages for the release of hundreds of Palestinian prisoners, an Israeli source told CNN, indicating the fragile Gaza ceasefire remains intact for now.

Palestinian medics say at least six infants have died from hypothermia in the last two weeks in the Gaza Strip.

At least six babies have died in the past two weeks in Gaza due to the cold weather and lack of adequate shelter and heating, Palestinian medics and health officials say.

The deaths highlighted the brutal humanitarian conditions in the Palestinian enclave despite a ceasefire, doctors said.