Israel has now evacuated the eastern third of Rafah. The United Nations has warned that the planned full-scale Rafah invasion would further cripple humanitarian operations and cause a surge in civilian deaths.

Israeli troops have captured the Gaza side of the Rafah crossing, forcing it to shut down. Egypt has refused to coordinate with Israel on the delivery of aid though the crossing because of “the unacceptable Israeli escalation,” Al Qahera News television channel reported, citing an unnamed official.

U.S. President Joe Biden has said he won't provide offensive weapons to Israel for Rafah. On Friday, his administration said there was “reasonable” evidence that Israel had breached international law protecting civilians — Washington's strongest statement yet on the matter.

More than 1.4 million Palestinians — half of Gaza’s population — have been sheltering in Rafah, most after fleeing Israel’s offensives elsewhere. The latest evacuations are forcing some to return north, where areas are devastated from previous attacks. Aid agencies estimate that 110,000 had left before Saturday's order that adds 40,000.

“Do we wait until we all die on top of each other? So we’ve decided to leave,” Rafah resident Hanan al-Satari said as people rushed to load mattresses, water tanks and other belongings onto vehicles.

"The Israeli army does not have a safe area in Gaza. They target everything,” said Abu Yusuf al-Deiri, displaced earlier from Gaza City.

Many people have been displaced multiple times. There are few places left to go. Some Palestinians are being sent to what Israel has called humanitarian safe zones along the Muwasi coastal strip, which is already packed with about 450,000 people in squalid conditions.

Georgios Petropoulos, with the U.N. humanitarian agency in Rafah, said that aid workers had no supplies to help people set up in new locations.

“We simply have no tents, we have no blankets, no bedding,” he said.

The World Food Program said it would run out of food to distribute in southern Gaza by Saturday, Petropoulos said — a further challenge as parts of Gaza face what the WFP chief has called “full-blown famine.” Aid groups have said that fuel will be depleted soon, forcing hospitals to shut down critical operations.

Heavy fighting was also underway in northern Gaza, where Israel's army spokesman Daniel Hagari said that the air force was carrying out airstrikes.

Palestinians in Jabaliya, Beit Lahiya and surrounding areas were told to leave for shelters in the west of Gaza City, warned that Israel would strike with “great force.”

Israel’s bombardment and ground offensives in Gaza have killed more than 34,800 Palestinians, mostly women and children.

Civil authorities in Gaza gave more details of mass graves that the Health Ministry announced earlier at Shifa hospital, the largest in northern Gaza and the target of an earlier Israeli offensive. Authorities said most of the 80 bodies were patients who died from lack of care.

At least 19 people, including eight women and eight children, were killed overnight in central Gaza in strikes that hit Zawaida, Maghazi and Deir al-Balah, according to Al Aqsa Martyrs Hospital and an AP journalist who counted the bodies.

“Children, what is the fault of the children who died?” one relative said. A woman stroked the face of one of the children lying on the ground.

Another round of cease-fire talks in Cairo ended earlier this week without a breakthrough, after Israel rejected a deal that Hamas said it accepted.