By Nidal al-Mughrabi

CAIRO/GAZA (Reuters) -Hamas is seeking guarantees that a new U.S. ceasefire proposal for Gaza would lead to the war's end, a source close to the militant group said on Thursday, as medics said Israeli strikes across the territory had killed scores more people.

Israeli officials said prospects for reaching a ceasefire deal and hostage deal appeared high, nearly 21 months since the war between Israel and Hamas began.

Efforts for a Gaza truce have gathered steam after the U.S. secured a ceasefire to end a 12-day aerial conflict between Israel and Iran, but on the ground in Gaza intensified Israeli strikes continued unabated, killing at least 59 people on Thursday, according to health authorities in the territory.

On Tuesday, U.S. President Donald Trump said that Israel had accepted the conditions needed to finalise a 60-day ceasefire with Hamas, during which the parties will work to end the war.

Hamas is seeking clear guarantees that the ceasefire will eventually lead to the war's end, the source close to the group said. Two Israeli officials said that those details were still being worked out.

Ending the war has been the main sticking point in repeated rounds of failed negotiations.

Egyptian security sources said Egyptian and Qatari mediators were working to secure U.S. and international guarantees that talks on ending the war would continue as a way of convincing Hamas to accept the two-month truce proposal.

A separate source familiar with the matter said that Israel was expecting Hamas' response by Friday and that if it was positive, an Israeli delegation would join indirect talks to cement the deal.

The proposal includes the staggered release of 10 living Israeli hostages and the return of the bodies of 18 more in exchange for Palestinian prisoners held in Israeli jails, sources say. Of the 50 remaining hostages in Gaza, 20 are believed to still be alive.

A senior Israeli official close to Prime Minister Benjamin Netanyahu said preparations were in place to approve a ceasefire deal even as the premier heads to Washington to meet Trump on Monday.

'READINESS TO ADVANCE'

Israeli Energy Minister Eli Cohen, who sits on Netanyahu's security cabinet, told news website Ynet that there was "definitely readiness to advance a deal."

In Gaza, however, there was little sign of relief. At least 17 people were killed in an Israeli strike that hit a school in Gaza City where displaced families were sheltering, according to medics.

"Suddenly, we found the tent collapsing over us and a fire burning. We don’t know what happened," one witness, Wafaa Al-Arqan, told Reuters. "What can we do? Is it fair that all these children burned?"

According to medics at Nasser hospital farther south, at least 20 people were killed by Israeli fire en route to an aid distribution site.

The Israeli military said it was looking into the reports and that its forces were taking precautions to mitigate harm to civilians as it battled Palestinian militants throughout Gaza.

The war began when Hamas fighters stormed into Israel on October 7, 2023, killing 1,200 people and taking 251 hostages back to Gaza, according to Israeli tallies.

Israel's subsequent military assault has killed more than 57,000 Palestinians, according to the Gaza health ministry, while displacing most of the population of more than 2 million, triggering widespread hunger and leaving much of the territory in ruins.

Israel says it won't end the war while Hamas is still armed and ruling Gaza. Hamas, severely weakened, says it won't lay down its weapons but is willing to release all the hostages still in Gaza if Israel ends the war.

(Additional reporting by Maayan Lubell in Jerusalem and Ahmed Salaby in Cairo; Editing by Aidan Lewis)