There were signs Sunday that a long elusive ceasefire to end fighting between Israel and the militant group Hamas in Gaza could be reached in the coming days, along with the release of the remaining hostages held by the militants.

A top-level Israeli security delegation arrived in Qatar for new talks with Qatari, Egyptian and U.S. officials, according to a spokesperson for Israeli Prime Minister Benjamin Netanyahu. They are making new efforts to reach an agreement before U.S. President Joe Biden leaves office January 20 and President-elect Donald Trump is inaugurated.

Biden’s national security adviser, Jake Sullivan, told CNN’s “State of the Union” show that the parties were “very, very close” to reaching a deal to halt more than 15 months of fighting in Gaza and free the remaining 98 hostages held there, with two-thirds of them believed to be alive.

“We are still determined to use every day we have in office to get this done,” he said. “We are not, by any stretch of imagination, setting this aside.”

Biden spoke Sunday with Netanyahu about the ongoing negotiations, the White House said, but did not disclose any details of the talks.

Sullivan said Biden is receiving daily updates on the Doha talks and that some progress has been made in the indirect talks between Israel and Hamas.

He said there was still a chance to reach an agreement before Biden leaves office, but not a certainty, saying that “Hamas, in particular, remains intransigent.”

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

Since then, more than 46,000 people have been killed in Gaza, with most of them women and children, according to Palestinian health officials, although Israel says the death toll includes thousands of Hamas combatants it has killed.

Much of Gaza, a narrow strip of land along the Mediterranean Sea, has been laid to waste during the fighting and gripped by a humanitarian crisis, with most of its 2.3 million population displaced, often multiple times.

Netanyahu’s office said Saturday that the Israeli delegation to the Doha talks includes the director of the Mossad intelligence agency, David Barnea; the head of the Shin Bet domestic security service, Ronen Bar; and the military’s head of hostage concerns, Nitzan Alon.

Trump’s Middle East envoy, Steve Witkoff, met Saturday with Netanyahu, after having met with Qatari Prime Minister Sheikh Mohammed bin Abdulrahman Al Thani on Friday.

Israeli and Palestinian officials have said since Thursday that some progress has been made in the indirect talks between Israel and Hamas, but did not elaborate. The sides have been keeping a tight lid on the details being worked out.

It is not clear how they will bridge one of the biggest gaps that has persisted throughout previous rounds of talks: Hamas demands an end to the war while Israel says it will not end the war as long as Hamas rules Gaza and poses a threat to Israelis.

Some material in this report came from Reuters.