Israel has broadly accepted a deal for a six-week Gaza ceasefire and it is now up to Hamas to agree to release the most vulnerable hostages for the deal to take effect, a senior US official said Saturday.

"There's a framework deal. The Israelis have more or less accepted it," the Biden administration official told reporters on a call, speaking on condition of anonymity. 

"Right now, the ball is in the camp of Hamas."

Negotiators from regional powers were working "around the clock" to secure the deal by the start of the Muslim holy month of Ramadan, which is due to start in about one week.

"It will be a six-week ceasefire in Gaza starting today if Hamas agrees to release the defined category of vulnerable hostages... the sick, the wounded, elderly and women," the official added.

"I just want to kind of emphasize that we would have a ceasefire if Hamas addresses that final issue."

US officials hope such a deal would create space for a "more enduring" peace settlement between Israel and Hamas, at war since the Palestinian militant group's October 7 attack on Israel.

A Hamas delegation was expected to fly to Cairo on Saturday for talks on a truce, a source close to the group told AFP.

The ceasefire would also allow a "significant surge" in humanitarian aid to Gaza, with the UN warning of an imminent famine in the north of the besieged territory.

The United States announced earlier Saturday that it had carried out its first airdrop of aid into Gaza, following a deadly incident at an aid station on Thursday in which more than 100 Palestinians died.

But US officials said this could not replace the need for as much relief as possible to move by land into Gaza. 

"None of these -- maritime corridors, air drops -- are an alternative to the fundamental need to move assistance through as many land crossings as possible. That's the most efficient way to get aid in at scale," a second US official told reporters on condition of anonymity