Israel has broadly accepted a ceasefire deal with Hamas, a senior US official said Saturday, as the first American airdrops of humanitarian aid were carried out over war-ravaged Gaza.

The framework agreement envisages a six-week cessation of hostilities, which could begin immediately if the Palestinian group signs off on the release of the most vulnerable hostages it holds, the official told reporters on a call.

"The Israelis have more or less accepted it," the administration official said. "Right now, the ball is in the camp of Hamas."

The announcement came hours after US military cargo planes began airdropping humanitarian aid into the besieged Gaza Strip.

The United Nations has warned of famine in Gaza, and more than 100 people were left dead earlier this week in a frenzied scramble for food from a truck convoy delivering aid, with Israeli forces opening fire on the crowd.

Saturday's drop, which included 38,000 meals, was conducted "to provide essential relief to civilians affected by the ongoing conflict," the US Central Command said.

A CENTCOM official told AFP that the meals were made up of US military rations that did not contain pork, the consumption of which is prohibited by Islam.

Negotiators working around the clock 

Negotiators from regional powers have been working around the clock to secure a Gaza truce by the start of the Muslim holy month of Ramadan 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 administration official said.

Around 130 Israeli hostages remain in Gaza, including 31 whom Israel says are presumed dead. It was unclear how many of the remaining hostages are deemed vulnerable.

The United States hopes any truce would create space for a more enduring peace. 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 administration official said a ceasefire would also allow a "significant surge" in humanitarian aid to Gaza, with airdrops not seen as a replacement for full-scale relief convoys.

"None of these -- maritime corridors, airdrops -- 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.

Ground route still key 

Hundreds of protesters rallied in Washington on Saturday, shouting slogans like "Free free Palestine" outside the Israeli embassy before marching with a giant Palestinian flag to the Israeli ambassador's residence.

Some held signs paying tribute to the US airman who died after self-immolating outside the Israeli embassy last weekend, shouting "Free Palestine" as he lit himself on fire, according to footage shared on social media.

Israel's war on Gaza has taken a devastating toll on civilians trapped there, killing more than 30,000 people, including over 13,000 children.

The amount of aid brought into Gaza by truck has plummeted during nearly five months of war, and Gazans are facing dire shortages of food, water and medicines.

Some foreign militaries have airdropped supplies to Gaza, sending long lines of aid pallets floating down into the war-torn territory on parachutes.

Jordan has been conducting many of the operations with the support of countries including Britain, France and the Netherlands, while Egypt sent several military planes on an air drop Thursday together with the United Arab Emirates.

Biden has pushed Israel to reduce civilian casualties and allow aid in, while at the same time he has maintained military assistance for the key US ally.

National Security Council spokesman John Kirby described the airdrops as a "tough military operation" that required careful planning by the Pentagon for the safety of both Gazan civilians and US military personnel.