United States President Joe Biden has spoken to Israeli Prime Minister Benjamin Netanyahu about the ongoing talks for a ceasefire in Gaza and stressed the “immediate need” for a truce, as well as the return of Israeli captives held in the Palestinian enclave.

The call on Sunday came as Biden pushes for a deal to stop the fighting before President-elect Donald Trump returns to the White House on January 20.

The negotiations, mediated over the past year by the US, Egypt and Qatar, have repeatedly stalled at moments when they seemed close to a deal. Still, in recent days, US officials have expressed hope of sealing an agreement.

The latest round is taking place in the Qatari capital, Doha, with the head of Israel’s Mossad foreign intelligence agency, David Barnea, as well as Biden’s top Middle East adviser, Brett McGurk, both attending the talks.

Barnea’s presence, confirmed by Netanyahu’s office, means high-level Israeli officials who would need to sign off on any agreement are now involved in the talks.

McGurk has been working on final details of a text to be presented to both sides, Biden’s national security adviser, Jake Sullivan, told CNN’s “State of the Union”. But he said he would not predict whether a deal can be reached by January 20, the day of the inauguration.

“We are very, very close,” he said. “Yet being very close still means we’re far because until you actually get across the finish line, we’re not there.”

The White House said the ongoing talks in Doha are for a deal based on the phased ceasefire that Biden had announced in May of last year, which was later endorsed unanimously by the United Nations Security Council.

Biden “stressed the immediate need for a ceasefire in Gaza and return of the hostages with a surge in humanitarian aid enabled by a stoppage in the fighting under the deal”, the White House said.

For his part, Netanyahu thanked Biden for his lifelong support of Israel, according to the White House readout. The Israeli prime minister has previously signalled that he is committed only to the first phase of the ceasefire agreement, which envisions the release of some captives in exchange for a weeks-long halt in fighting.

Hamas, however, has insisted on a full Israeli troop withdrawal from the largely devastated territory, but Netanyahu remains intent on destroying the group’s ability to fight in Gaza.

Issues in the talks have included which captives would be released in the first part of a phased ceasefire deal, which Palestinian prisoners would be released and the extent of any Israeli troop withdrawal from population centres in Gaza.

Al Jazeera’s Hamdah Salhut, reporting from Jordan, said the Israeli negotiating team in Qatar is expected to stay in the country for at least another day “in order to hammer out final details for a potential deal”.

She noted that the Israelis and Hamas have traded blame for the delay in reaching a deal, while there is disagreement among Netanyahu’s coalition about a ceasefire.

“Members of the far-right have said they would vote against it and Netanyahu has even spoken to members of the far-right, including Finance Minister Bezalel Smotrich to try to warm them up to the idea of a deal,” she said. “There is a school of thought in Israel that Netanyahu has prolonged the war and not agreed to a deal because he fears it could result in the collapse of his government. But nonetheless, these talks are still ongoing as mediators are scrambling to get a deal.”

The talks come as Israel continues its relentless bombardment of the Gaza Strip, particularly the north of the enclave, which has been subject to a brutal siege for more than 100 days. Medical sources in Gaza say 5,000 people have been killed or are missing due to the ongoing attacks.

Israel’s campaign in Gaza has killed more than 46,000 Palestinians, the majority women and children, and displaced more than 90 percent of the territory’s population from their homes. The brutal war, which some UN experts describe as “genocide”, began in the aftermath of the Hamas-led attack on Israel on October 7, 2023, in which Palestinian fighters killed 1,200 people and took some 250 others captive.

Just one brief ceasefire has been achieved in 15 months of war, in the earliest weeks of fighting.