DOHA, Qatar — International mediators held a new round of talks Thursday aimed at halting the Israel-Hamas war and securing the release of scores of hostages, with a potential deal seen as the best hope of heading off an even larger regional conflict.

The United States, Qatar and Egypt met with an Israeli delegation in Qatar as the Palestinian death toll from the more than 10-month-old war climbed past 40,000, according to Gaza health authorities. Hamas, which didn’t participate directly, accuses Israel of adding new demands to a previous proposal that had U.S. and international support and to which Hamas had agreed in principle.

White House National Security spokesman John Kirby called the talks an important step and said they’re expected to run into Friday. He said a lot of work remains given the complexity of the agreement and that negotiators were focusing on its implementation.

A cease-fire in Gaza would likely calm tensions across the region. Diplomats hope it would persuade Iran and Lebanon’s Hezbollah to hold off on retaliating for the killing of a top Hezbollah commander in an Israeli airstrike in Beirut and of Hamas’ top political leader in an explosion in Tehran.

Kirby said that Iran has made preparations and could attack soon with little to no warning and that its rhetoric should be taken seriously.

The mediators have spent months trying to hammer out a three-phase plan in which Hamas would release scores of hostages captured in the Oct. 7 attack that triggered the war in exchange for a lasting cease-fire, the withdrawal of Israeli forces from Gaza and the release of Palestinians imprisoned by Israel.

Both sides have agreed in principle to the plan, which President Joe Biden announced on May 31. But Hamas has proposed “amendments” and Israel has suggested “clarifications,” leading each side to accuse the other of making new demands it can’t accept.

DETAILS OF AGREEMENT

Hamas has rejected Israel’s latest demands, which include a lasting military presence along the border with Egypt and a line bisecting Gaza where it would search Palestinians returning to their homes to root out militants. Hamas spokesman Osama Hamdan told The Associated Press that the group is only interested in discussing the implementation of Biden’s proposal and not in further negotiations over its content.

A Palestinian official who closely follows the negotiations said Hamas wouldn’t take part in Thursday’s talks, but that its senior officials, who reside in Qatar, were ready to discuss any proposals from the mediators, as they have in past rounds.

Israeli Prime Minister Benjamin Netanyahu denies that Israel has made new demands, but he has also repeatedly raised questions over whether the cease-fire would last, saying Israel remains committed to “total victory” against Hamas and the release of all the hostages.

The most intractable dispute has been over the transition from the first phase of the cease-fire — when women, children and other vulnerable hostages would be released — and the second, when captive Israeli soldiers would be freed and a permanent cease-fire would take hold.

Hamas is concerned that Israel will resume the war after the first batch of hostages is released. Israel worries that Hamas will drag out the talks on releasing the remaining hostages indefinitely. Hamdan provided documents showing Hamas had agreed to a U.S. bridging proposal under which talks on the transition would begin by the 16th day of the first phase and conclude by the fifth week.

More recently, Hamas has objected to what it says are new Israeli demands to maintain a presence along the Gaza-Egypt border and a road dividing northern and southern Gaza. Israel denies these are new demands, saying it needs a presence along the border to prevent weapons smuggling and that it must search Palestinians returning to northern Gaza to ensure they aren’t armed.

The demands were made public only recently. Hamas has demanded a full Israeli military withdrawal, which was also part of all previous versions of the cease-fire proposal, according to documents shared with the AP that were verified by officials involved in the negotiations.

ORIGINS OF CONFLICT

The war began when Hamas-led militants stormed across the heavily guarded border on Oct. 7 in an attack that shocked Israel’s vaunted security and intelligence services. The fighters rampaged through farming communities and army bases, killing around 1,200 people, mostly civilians.

Israel’s retaliatory offensive has killed 40,005 Palestinians, Gaza’s Health Ministry said Thursday, without saying how many were militants. The offensive has left a swath of destruction across the territory and driven the vast majority of Gaza’s 2.3 million people from their homes, often multiple times.

While mediation to end the war is ongoing, violence continued in the occupied West Bank on Thursday, when one Palestinian was shot dead and another was critically injured by Israeli settlers, according to Palestinian health officials. Israeli and Palestinian media said that masked settlers stormed the village of Jit in the northern West Bank, setting homes and cars on fire.

In a rare statement Thursday night, Netanyahu condemned the attack, saying it was the responsibility of the army to secure the country, and that those responsible for the attack would be apprehended and prosecuted.

Israel’s military said it has apprehended a civilian who took part in the violence and has opened an investigation.

Information for this article was contributed by Bassem Mroue, Wafaa Shurafa, Aamer Madhani and David Klepper of The Associated Press.