Israel and Hamas agreed on Wednesday to the first phase of US President Donald Trump’s plan for Gaza, a ceasefire and hostage deal that could be a first step toward ending a bloody two-year-old war that has roiled the Middle East.

Here are some details of what is known and not known so far:

What do we know about the deal?

The agreement on the initial stage of Trump’s 20-point framework resulted from indirect talks in Egypt, just a day after the second anniversary of Hamas’s attack on Israel that triggered Israel’s devastating assault on Gaza.

Trump announced that both Israel and Hamas had signed off on the first phase of the plan and this would bring the release of all hostages, alive and dead, “very soon” and the withdrawal of Israeli troops to the so-called yellow line in Gaza. According to a senior Israeli security source, that is a boundary for an initial Israeli pullback under the Trump plan.

Hamas confirmed it had reached an agreement to end the war, that includes an Israeli withdrawal from Gaza and a hostage-prisoner exchange, but the group called on Trump and guarantor states to ensure Israel fully implements the ceasefire.

What are the main unknowns?

Despite the hopes raised for ending the war, crucial details are yet to be spelled out.

These include the timing, a post-war administration for the Gaza Strip and the fate of Hamas.

There is no clear indication who will rule Gaza when the war ends. Netanyahu, Trump, Western and Arab states have ruled out a role for Hamas, which has run Gaza since driving out Palestinian rivals in 2007.

Trump’s original 20-point plan envisions a role for the Palestinian Authority but only after it has undergone major reforms.

What happens next?

Israeli Prime Minister Benjamin Netanyahu said he would convene his government on Thursday to approve the agreement.

A Hamas source said the living hostages would be handed over within 72 hours of the Israeli government approving the deal. Israel said the hostage release was expected to begin on Saturday. Of the 48 hostages, 20 are still thought to be alive.

A senior White House official said once Israel approves the deal it has to withdraw to the agreed line, which should take under 24 hours, after which the 72-hour clock would begin. The White House expects the hostages will begin getting released on Monday.

Hamas said earlier on Wednesday it had handed over its lists of the hostages it held and the Palestinian prisoners held by Israel that it wanted to be exchanged.

Trump is expected to travel to Egypt in the coming days as the White House said he was considering going to the region on Friday. Netanyahu has invited Trump to address Israel’s parliament and Trump told Axios he would be willing to do that.

The next phase of Trump’s plan calls for an international body, called the “Board of Peace,” to play a role in Gaza’s post-war administration. It is to be led by Trump and include former British Prime Minister Tony Blair.

What are the biggest risks to the deal?

Successful completion of the deal would mark the biggest foreign policy achievement so far for Trump, who took office in January promising to quickly end the wars in Gaza and Ukraine, only to find that they were more difficult to resolve than he had hoped.

Hamas has so far refused to discuss Israel’s demand that the militant group give up its arms. A Palestinian source said Hamas would reject this as long as Israeli troops occupy Palestinian land.

Two sources familiar with the talks confirmed that sticking points included the mechanism for the Israeli withdrawal, with Hamas seeking a clear timeline linked to the release of hostages and guarantees of a complete pullout by Israeli forces.

Within Gaza, Israel has dialed down its military campaign at Trump’s behest, but it has not halted strikes altogether.

Arab countries which back the plan say it must lead to eventual independence for a Palestinian state, which Netanyahu says will never happen.

Hamas has said it would relinquish Gaza governance only to a Palestinian technocrat government supervised by the Palestinian Authority and backed by Arab and Muslim countries. It rejects any role for Blair or foreign rule of Gaza.

The list of Palestinians that Hamas wants freed was expected to include some of the most prominent prisoners ever jailed by Israel, whose release had been off limits in previous ceasefires.

According to a Palestinian source close to the talks, the list includes Marwan al-Barghouti, a leader of the Fatah movement, and Ahmed Saadat, head of the Popular Front for the Liberation of Palestine. Both are serving multiple life sentences for involvement in attacks that killed Israelis.