The first phase of the ceasefire that paused 15 months of brutal warfare between Israel and Hamas militants is set to end on Saturday, and it’s unclear what comes next.

The two sides were supposed to start negotiating a second phase weeks ago in which Hamas would release all the remaining hostages from its Oct. 7, 2023, attack, which triggered the war, in exchange for more Palestinian prisoners, a lasting ceasefire and a full Israeli withdrawal from the Gaza Strip.

But those negotiations have not begun — there have only been preparatory talks — and the first phase has been jolted by one dispute after another.

Hamas has freed all 25 living hostages included in the first six-week phase ending on March 1 in exchange for hundreds of Palestinian prisoners. It has also released the bodies of four captives and is expected to turn over four more, though it’s unclear if that will happen Thursday as planned.

That leaves it with more than 60 captives, around half of whom are believed to be dead. Israel has meanwhile delayed the release of some 600 Palestinian prisoners who were supposed to be freed last weekend over the treatment of the captives, who were paraded before crowds.

Israel is reportedly seeking an extension of the first phase to secure the freedom of more captives. But Hamas says it won’t negotiate anything until the prisoners whose release was delayed are freed.

Negotiations over Phase 2 will be even more contentious.

The second phase was always going to be the most difficult because it would likely force Israel to choose between its two main war goals — the safe return of the hostages and the annihilation of their captors.

Hamas, though weakened, remains in power with no internal challengers. In exchange for the remaining living hostages — its main bargaining chip — it is demanding a lasting ceasefire and the full withdrawal of Israeli forces. A third phase would see the exchange of remains and the start of Gaza’s daunting reconstruction process, which is expected to take years and cost billions of dollars.

Steve Witkoff, the Trump administration’s Mideast envoy, is returning to the region this week. In an interview with CNN’s “State of the Union” on Sunday, he said he will aim for an extension of Phase 1 to buy time for negotiating the second phase.

But Egypt, which has served as a key mediator, has refused to discuss an extension of Phase 1 until negotiations over Phase 2 begin, according to two Egyptian officials who were not authorized to brief reporters and spoke on condition of anonymity.

One official familiar with the negotiations said the mere launch of Phase 2 talks would keep the truce intact, according to the language of the deal. That would mean a continued halt in fighting and aid flowing into Gaza, though there would be no further hostage releases beyond what has already been negotiated, he said, speaking on condition of anonymity to discuss closed diplomatic contacts.

Hamas has previously said it is open to a short extension to complete talks on Phase 2, but that was before Israel held up the release of the prisoners.