US Vice President Kamala Harris called Sunday for a proposed six-week ceasefire deal in the Israel-Hamas war to be accepted, while criticizing Israel over insufficient aid deliveries into Gaza.

"Given the immense scale of suffering in Gaza, there must be an immediate ceasefire for at least the next six weeks, which is what is currently on the table," Harris said during a speech in Selma, Alabama.

Her comments were the strongest to date by a US administration official on Israel, as President Joe Biden comes under acute pressure over his support for Israel and the civilian death toll in Gaza soars.

A senior US official said Saturday that Israel had broadly accepted the deal, which would see a six-week cessation of hostilities if Hamas agrees to release the most vulnerable hostages it holds.

The deal "will get the hostages out and get a significant amount of aid in," Harris said, calling on Hamas to accept the deal.

"Hamas claims it wants a ceasefire. Well, there is a deal on the table. And as we have said, Hamas needs to agree to that deal."

The Israeli army says 130 hostages remain in Gaza, of whom 31 are believed to be dead.

Israel's military response has claimed 30,410 deaths, most of them women and children, according to the Hamas government's Ministry of Health.

In unusually strong language, Harris called on the government of Prime Minister Benjamin Netanyahu to take steps to increase aid into Gaza.

"The Israeli government must do more to significantly increase the flow of aid. No excuses," Harris said.

She added that Israel "must open new border crossings" and "must not impose any unnecessary restrictions on the delivery of aid."

Harris is due to meet with Benny Gantz, a centrist member of Israel's war cabinet, in Washington on Monday.

"The vice president's meeting is part of our continued efforts to engage with a wide range of Israeli officials on the war in Gaza and planning for the day after," a White House official said Sunday.

The former Israeli military chief, a longtime rival of Netanyahu, will also meet White House national security advisor Jake Sullivan and US Secretary of State Antony Blinken, according to US officials.

"Too many innocent Palestinians have been killed," Harris said, highlighting the deaths on Thursday in chaotic scenes around a convoy of aid trucks.

People "simply trying to secure food for their families after weeks of nearly no aid reaching northern Gaza... were met with gunfire and chaos," said Harris, adding: "Our hearts break for the victims of that horrific tragedy."

"The threat Hamas poses to the people of Israel must be eliminated."

Harris delivered her remarks at the foot of the Edmund Pettus Bridge, where a march by hundreds of peaceful activists was violently suppressed by police on March 7, 1965.

The event, known as "Bloody Sunday," further catalyzed support for Black rights and helped lead a few months later to the passage of the Voting Rights Act, a federal law prohibiting racial discrimination in voting.