The terms of an agreement between Israel and Hamas on a ceasefire in Gaza and the release of hostages are being finalized, a Palestinian official familiar with the negotiations told the BBC.

White House national security adviser Jake Sullivan said a truce and hostage deal could be reached “this week.”

An Israeli official also told Reuters that talks were in “advanced stages” and a deal could be reached within “hours, days or longer.”

US President Joe Biden spoke with Israeli Prime Minister Benjamin Netanyahu on Sundayand a meeting on Monday with Qatari Sheikh Tamim bin Hamad Al Thani, who is mediating the negotiations.

Sullivan said Biden will also speak with Egyptian President Abdel Fattah al-Sisi.

Hamas and Israeli officials held indirect talks in the same building on Monday, Palestinian officials told the BBC.

Netanyahu faces strong opposition within his ruling coalition to his potential deal.

Ten right-wing members, some from Netanyahu’s own Likud party, have sent him a letter opposing the ceasefire.

Meanwhile, Gaza’s civil defense agency reported that a wave of Israeli air strikes on Gaza City on Monday killed more than 50 people.

“They bombed schools, homes and even crowd gatherings,” civil defense spokesman Mahmoud Bassal told AFP.

The Israeli military said it was investigating the reports. Separately, five soldiers were allegedly killed in the northern Gaza Strip on Monday.

The war was triggered by a Hamas attack on southern Israel on October 7, 2023, which killed about 1,200 people and took 251 others hostage to Gaza.

In response, Israel launched a military offensive into Gaza to destroy Hamas.

The Hamas health ministry in Gaza said more than 46,500 people have been killed during the war.

Israel says 94 hostages remain in Gaza, 34 of whom are presumed dead, and four hostages abducted before the war, two of whom have died.