The launch of Israel’s long-planned assault on Rafah, the last unoccupied part of the Gaza Strip, has created a humanitarian catastrophe, displacing tens of thousands of Palestinians and threatening the entire population with starvation.

On Monday, the Israeli military dropped leaflets over portions of Rafah, instructing over 100,000 people to leave the area immediately. This was followed on Tuesday by an Israeli offensive to seize the Rafah crossing to Egypt, leading to the total suspension of the entry of humanitarian aid into the territory.

No aid trucks have entered Rafah since Sunday, the UN said, warning that “fuel stocks in Gaza will be depleted within days.”

Much of Gaza, particularly in the north, is already suffering a “full-blown famine,” Cindy McCain, the head of the World Food Program, said Saturday. And every day that the Rafah crossing is shut down, the more desperate the humanitarian situation becomes.

Andrea De Domenico, head of operations in the Palestinian territories for the UN Office for the Coordination of Humanitarian Affairs, said Tuesday that most food distribution in southern Gaza was halted Monday. He added that unless more supplies are allowed in, the “treatment of more than 3,000 children with acute malnutrition will be interrupted.”

While Israeli officials claimed they would reopen the Rafah crossing Wednesday, UN officials made clear that it remained effectively closed due to ongoing military operations in the area.

“The crossing area has ongoing military operations and is an active war zone,” said UNRWA spokesperson Louise Wateridge. “We are hearing continued bombardments in this area throughout the day. No fuel or aid has entered into the Gaza Strip, and this is disastrous for the humanitarian response.”

Gazan officials said Israeli forces carried out an attack on border employees Wednesday when they attempted to retrieve aid near the crossing.

“With that crossing now being closed, our whole humanitarian operation on the ground is compromised,” said Ricardo Pires, a spokesman for the United Nations Children’s Agency. “If the crossing is not urgently reopened, the entire civilian population in Rafah and in the Gaza Strip will be at greater risk of famine, disease and death,” he said.

An estimated 1.2 million displaced people are currently crowded in Rafah under squalid conditions, without sufficient food, water, sanitation or medicine. This figure includes over 600,000 children who are “highly vulnerable and at the edge of survival,” the United Nations Children’s Fund wrote.

Over 1 million Gazans are facing “catastrophic” food insecurity, with one-third of children under the age of two suffering from acute malnutrition.

The acute starvation of the population is coupled with the effect of perpetual bombing. The Euro-Med Monitor reported Wednesday, “In less than 48 hours, this bombardment has resulted in the destruction of approximately 18 homes, the majority of which collapsed on top of their occupants’ heads, killing 52 Palestinians, including 17 children and 14 women.”

Israel’s evacuation orders for sections of Rafah have caused panic, with people attempting to flee without adequate transportation and fuel. Food prices have surged.

“Since 6 May, tens of thousands of people, many of whom have already been displaced multiple times, have been forced to leave Rafah governorate in search of increasingly limited options for safety,” the UN’s humanitarian office wrote. It added, “the few sites to which people are already relocating are without adequate latrines, water points, drainage, or shelter, but humanitarian agencies are unable to improve conditions with no fuel and other supplies coming in.”

Despite repeated claims by the United States that an attack on Rafah had not begun, the United Nations was categorical that an offensive was underway. “On 7 May, a ground operation by the Israeli military began in eastern Rafah, including the areas of Rafah and Kerem Shalom crossings as well as some 31 square kilometers where residents were ordered to evacuate on 6 May,” the UN noted.

“I am disturbed and distressed by the renewed military activity in Rafah,” UN Secretary-General António Guterres said Tuesday.

The United States has publicly stated that it opposes a full-scale Israeli assault on Rafah, even while making clear the US would continue to fund and arm the Israeli regime if the assault took place.

On Wednesday, US President Joe Biden said that the United States would consider blocking the transfer of some weapons to Israel “if they go into Rafah.”

Biden said, “if they go into Rafah, I’m not supplying the weapons that have been used historically, to deal with Rafah, to deal with the cities—that deal with that problem.” The syntax is muddled, to put it mildly, but Biden appeared to be referring to delaying shipments of 2,000-pound bombs that Israel has used to flatten entire city blocks and kill hundreds of people at a time.

Earlier in the day, US Secretary of Defense Lloyd Austin told a Senate committee that the US had stated “that Israel shouldn’t launch a major attack into Rafah without accounting for and protecting the civilians that are in that battle space, and again, as we have assessed the situation, we have paused one shipment of high payload munitions.”

Last week, the US temporarily held up a shipment of 2,000-pound and 500-pound bombs to Israel, US media sources reported.

Biden was categorical, however, that the United States would continue to provide other weapons to Israel, declaring, “We’re going to continue to make sure Israel is secure.”

He added, “We’re not walking away from Israel’s security.”

This was in keeping with Biden’s declaration in March, “There is no red line that I am going to cut off all weapons.”

Writing in the New York Times, journalist Peter Baker noted, “The Biden administration is still allowing most other weapons to be sent to Israel, and in fact, officials emphasized that no final decision has even been made on the bombs that are currently in limbo.” Baker’s article continued, “officials said they would still provide ‘every dollar’ of aid authorized in the new congressional package.”

Over the past seven months, the United States has provided over 100 separate arms shipments to Israel. The US provides Israel with $3.8 billion in annual funding, and Biden just signed into law a bill that sends billions more. The United States has provided more than $160 billion in weapons and funding to Israel since it was founded.

On Wednesday, Gaza’s media office reported that a third mass grave has been found at Shifa Hospital, containing at least 49 bodies, and that seven mass grave sites had been found at Gazan hospitals so far, containing more than 520 bodies. According to press reports, some of the bodies had been decapitated.

On Monday, a group of UN experts issued a statement declaring, “We are horrified at details emerging from mass graves recently unearthed in the Gaza Strip. Over 390 bodies have been discovered at Nasser and Al Shifa hospitals, including of women and children, with many reportedly showing signs of torture and summary executions, and potential instances of people buried alive.”