Palestinian movement Hamas refused to "back down" on Saturday from its demands for a Gaza ceasefire but agreed to send a delegation for renewed talks in Cairo over the weekend.

"Hamas confirms its adherence to the position it presented on March 14 ... and we will not back down from this position," it said in a statement.

The group also reiterated its series of demands.

"The demands ... are complete ceasefire, withdrawal of the occupation forces from Gaza, the return of the displaced to their residential areas, freedom of movement of the people, offering them aid and shelter, and a serious hostage exchange deal," it said.

Negotiators were expected in Cairo over the weekend for a renewed push to strike a ceasefire and hostage exchange deal with the war in Gaza set to reach the six-month mark on Sunday.

Hamas's insistence on its demands came as US President Joe Biden urged an "immediate ceasefire" in Gaza.

Ahead of the weekend talks, Biden wrote to the leaders of Egypt and Qatar urging them to secure commitments from Hamas to "agree to and abide by a deal", a senior US administration official told AFP.

During a phone call with Israeli Prime Minister Benjamin Netanyahu on Thursday, Biden pushed him to "fully empower" his negotiators to reach a deal.

Stop-start talks have made no headway since a week-long truce in November, the only one since the start of the war on 7 October, saw the exchange of dozens of hostages held by Hamas in exchange for Palestinian prisoners detained by Israel.