A new round of talks toward finalizing a cease-fire in the Gaza Strip and an exchange of Israeli hostages for Palestinian prisoners got underway Thursday in Qatar without Hamas at the negotiating table.

The U.S., Qatar and Egypt are mediating the talks in Doha. An Israeli delegation is in attendance.

Hamas confirmed Wednesday it would not take part in the negotiations. Representatives from Qatar and Egypt will separately be in contact with Hamas, White House national security spokesman John Kirby told reporters Thursday.

Kirby said he does not anticipate an agreement being reached Thursday and expects the negotiations to continue at least into Friday.

“The resumption of these talks is an important step, and in the lead-up to this meeting, we’d already narrowed some gaps,” Kirby said. “Today, we are focused on the details of the implementation of the agreement. There remains a lot of work to do, given the complexity of the agreement.”

Diplomats hope a deal 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.

Israel and Hamas have agreed in principle to a plan that President Joe Biden announced May 31. However, each side has accused the other of making new demands it cannot accept.

The first of three phases in the proposed deal would last six weeks and establish a “full and complete cease-fire” as Israeli forces withdrew from densely populated areas of Gaza and humanitarian assistance into the region surged. Meanwhile, Hamas would release a number of hostages, including women, the elderly and the wounded in exchange for Israel freeing hundreds of Palestinian protesters.

The second phase calls for the release of all remaining living hostages and Israeli forces withdrawing from Gaza completely.

The final phase would focus on the reconstruction of Gaza.

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 spokesperson Osama Hamdan told The Associated Press the group is only interested in discussing the implementation of Biden’s proposal and not in further negotiations over its content.

Prime Minister Benjamin Netanyahu denies 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. 

Kirby insisted the talks have moved beyond the framework of the deal and are focused on “where the gaps are are in the execution of the deal, the individual muscle movements that go with putting the deal in place.”

Asked if he believes Israel has added new conditions, Kirby said, “I’m just not going to play in that game right now, not when we’re as close as we certainly hope to be today.”

Kirby downplayed Hamas’ absence from the talks, saying the process is in line with previous negotiations with the militant group.

“The process that is playing out in Doha is very much in keeping with the process that has played out in the past,” he said.

Meanwhile, the U.S. remains vigilant about a possible attack by Iran on Israel. Kirby warned earlier this week the U.S. believes Iran could launch a “significant” strike on Israel following the recent assassinations of Hamas’ top political leader, Ismail Haniyeh, and Hezbollah commander Fouad Shukr. 

Israel has claimed responsibility for the Shukr’s death but has not said if it launched the strike that killed Haniyeh.

The Pentagon announced this week it was accelerating the aircraft carrier USS Abraham Lincoln’s arrival to the region and relocating the guided missile submarine USS Georgia to the Middle East.

Kirby said the U.S. has been sending messages to Iran through intermediary countries with direct diplomatic relations with the country.  

“Our messages have been consistent: We don’t want to see an escalation here,” he said.

“Should Iran choose to go forward with some sort of an attack on on Iran … we’re ready for it — to defend ourselves, our facilities, our people, but also to defend Israel,” Kirby said. “ … We have to take it seriously, the rhetoric coming out of Tehran.”

CIA Director William Burks and Middle East envoy Brett McGurk are representing the U.S. at the talks.

The Associated Press contributed to this report.