More than eight hours of talks in Doha had fuelled optimism. Officials from mediators Qatar, Egypt and the U.S. as well as Israel and Hamas said an agreement for a truce in the besieged enclave and release of hostages was closer than ever.

Qatar's foreign ministry spokesperson Majed Al-Ansari earlier told a news conference that both sides were presented with a text and talks on the last details were under way.

But a senior Hamas official told Reuters late on Tuesday that the Palestinian group had not delivered its response yet because it was still waiting for Israel to submit maps showing how its forces would withdraw from Gaza.

U.S. President Joe Biden, whose administration has been taking part alongside an envoy of President-elect Donald Trump, said a deal was close.

Biden and Egyptian President Abdel Fattah El-Sisi talked about progress in the negotiations on Tuesday.

"Both leaders committed to remain in close coordination directly and through their teams over the coming hours," the White House said in a statement after the leaders' telephone call.

The two presidents "emphasized the urgent need for a deal to be implemented."

Hamas said the talks had reached the final steps and it hoped this round of negotiations would lead to a deal.

An Israeli official said talks had reached a critical phase although some details needed to be worked out: "We are close, we are not there yet."

Visiting Rome, Israeli Foreign Minister Gideon Saar said on Tuesday he believed a majority of Israel's coalition government would support a Gaza deal if one is finally agreed, despite vocal opposition from hardline nationalist parties in the coalition.

Militant group Islamic Jihad, which is separate from Hamas and also holds hostages in Gaza, said it was sending a senior delegation that would arrive in Doha on Tuesday night to take part in final arrangements for a ceasefire deal.

If successful, the phased ceasefire - capping over a year of start-and-stop talks - could halt fighting that decimated Gaza, killed tens of thousands of Palestinians, made most of the enclave's population homeless and is still killing dozens a day.

That in turn could ease tensions across the wider Middle East, where the war has fuelled conflict in the West Bank, Lebanon, Syria, Yemen and Iraq, and raised fears of all-out war between Israel and Iran.

Israel would recover around 100 remaining hostages and bodies from among those captured in the Oct. 7, 2023 attacks by Hamas that precipitated the war. In return it would free Palestinian detainees.

U.S. Secretary of State Antony Blinken, who gave a speech in Washington outlining a vision for governing the Palestinian territories after the war, said it was up to Hamas to accept a deal that was already set for implementation.

CHILDREN, WOMEN HOSTAGES WOULD BE RELEASED FIRST

"The deal ... would free the hostages, halt the fighting, provide security to Israel and allow us to significantly surge humanitarian assistance to the Palestinians who suffered terribly in this war that Hamas started," Biden said on Monday.

Despite the efforts to reach a ceasefire, new Israeli strikes in Gaza killed at least 15 people on Tuesday in attacks on Deir al-Balah and Rafah, medics said.

Meanwhile, the United Nations said it was busy preparing to expand humanitarian assistance to Gaza under a potential ceasefire but uncertainty around border access and security remained obstacles.

Families of hostages in Israel were caught between hope and despair.

"We can't miss this moment. This is the last moment; we can save them," said Hadas Calderon, whose husband Ofer and children Sahar and Erez were abducted.

An Israeli official said the deal's first stage would see the release of 33 hostages, including children, women including some female soldiers, men above 50, and the wounded and sick. Israel would gradually and partially withdraw some forces.

A Palestinian source said Israel would free 1,000 Palestinian prisoners in the first phase over 60 days.

Israel launched its assault in Gaza after Hamas-led fighters stormed across its borders on Oct. 7, 2023, killing 1,200 people and taking more than 250 hostages, according to Israeli tallies.

Since then, Israeli forces have killed more than 46,000 Palestinians in Gaza, according to Palestinian health officials.

Both sides have been committed in principle for months to the prospect of a ceasefire accompanied by a swap of remaining hostages for detainees. But Hamas rejected any deal that stopped short of bringing a permanent end to the war, while Israel said it would not end the war until Hamas is dismantled.

Trump's Jan. 20 inauguration is now widely seen as a de facto deadline for a ceasefire agreement.