Hamas handed over the bodies of four Israeli hostages while it waited for hundreds of Palestinian prisoners to be released by Israel in return, in an overnight exchange marking the final swap as part of a fragile truce in Gaza.

The ceasefire came into effect on January 19 and has largely held, despite numerous setbacks. But its first phase is due to end this week and the fate of its next phase, which aims to end the war, remains unclear.

Hamas said on Thursday that it was ready to start talks on the second phase, and that the only way remaining hostages would be freed is through commitment to the ceasefire.

After days of impasse, Egyptian mediators on Wednesday secured the handover of the bodies of the final four hostages in the deal’s first phase, for 620 Palestinians either detained by Israeli forces in Gaza or jailed in Israel.

Israel had refused to release prisoners on Saturday after Hamas handed over six hostages in a staged ceremony.