KHAN YOUNIS, Gaza Strip >> Israel said Wednesday that it will allow Egypt to deliver limited humanitarian aid to the Gaza Strip. The first crack in a punishing 10-day siege on the territory came one day after a blast at a hospital killed hundreds and put immense strain on Gaza’s struggling medical system.

The announcement to allow water, food and other supplies happened as fury over the blast at Gaza City’s al-Ahli Hospital spread across the Middle East, and as U.S. President Joe Biden visited Israel in hopes of preventing a wider conflict in the region.

There were conflicting claims of who was behind the explosion on Tuesday night, but protests flared quickly as many Arab leaders said Israel was responsible. Hamas officials in Gaza blamed an Israeli airstrike, saying hundreds were killed. Israel denied it was involved and released a flurry of video, audio and other information that it said showed the blast was instead due to a rocket misfire by Islamic Jihad, another militant group operating in Gaza. Islamic Jihad dismissed that claim.

The Associated Press has not independently verified any of the claims or evidence.

Israel shut off all supplies to Gaza soon after Hamas militants rampaged across communities in southern Israel on Oct. 7. As supplies run out, many families in Gaza have cut down to one meal a day and have been left to drink dirty water.

The bloody devastation at al-Ahli threw the siege’s impact into sharp relief. Video from the scene showed the hospital grounds strewn with torn bodies, many of them young children. Hundreds of wounded were rushed to Gaza City’s main hospital where doctors, already facing critical supply shortages, were sometimes forced to perform surgery on the floors, often without anesthesia.

A steady stream of ambulances, taxis, cars and at least one motorcycle also arrived at a hospital in Khan Younis. Men jumped from the vehicles and scrambled to open doors, with hospital staff and bystanders helping carry the injured.

One man rushed in carrying a limp child in his arms. A girl with her head wrapped with a makeshift bandage was helped from a car. Many injured had to be carried by multiple men or hoisted onto gurneys.

As soon as one vehicle was unloaded, another arrived to take its place.

Biden said Egypt’s president agreed to open the crossing and to let in an initial group of 20 trucks with humanitarian aid. If Hamas confiscates aid, “it will end,” he said. The aid will start moving Friday at the earliest, White House officials said.

Egypt must still repair the road across the border that was cratered by Israeli airstrikes. More than 200 trucks and some 3,000 tons of aid are positioned at or near the Rafah crossing, Gaza’s only connection to Egypt, said the head of the Red Crescent for North Sinai, Khalid Zayed.

Supplies will go in under supervision of the U.N., Egyptian Foreign Minister Sameh Shoukry told Al-Arabiya TV. Asked if foreigners and dual nationals seeking to leave would be let through, he said: “As long as the crossing is operating normally and the (crossing) facility has been repaired.”

Israeli Prime Minister Benjamin Netanyahu’s office said the decision was approved after a request from Biden. It said Israel “will not thwart” deliveries of food, water or medicine from Egypt, as long as they are limited to civilians in the south of the Gaza Strip and don’t go to Hamas militants. The statement made no mention of fuel, which is badly needed for hospital generators.

Relatives of some of the roughly 200 people who were taken hostage and forced back to Gaza during the attack reacted in fury to the aid announcement.

“Children, infants, women, soldiers, men, and elderly, some with serious illnesses, wounded and shot, are held underground like animals,” said a statement from the Hostage and Missing Families Forum. But “the Israeli government pampers the murderers and kidnappers.”

Palestinian rocket attacks on Israel resumed Wednesday after a 12-hour lull. Israeli strikes on Gaza continued, including on cities in the south that Israel had described as “safe zones” for civilians.

In his brief visit, Biden tried to strike a balance between showing U.S. support for Israel, while containing growing alarm among Arab allies. Upon his arrival, Biden embraced Netanyahu, said the hospital blast appeared not to be Israel’s fault and expressed concern for the suffering of Gaza’s civilians. He also announced $100 million in humanitarian aid for Palestinians in Gaza and the West Bank.

The Israeli military held a briefing Wednesday laying out its case for why it was not responsible for the explosion at the al-Ahli Hospital.

Spokesman Rear Adm. Daniel Hagari said the military was not firing in the area when the blast occurred. He said Israeli radar confirmed a rocket barrage was fired by Islamic Jihad militants from a nearby cemetery at the time of the blast. Independent video showed one rocket in the barrage falling out of the sky, he said.

The misfired rocket hit the parking lot outside the hospital, he said. Were it an airstrike, there would have been a large crater there; instead, the fiery blast came from the misfired rocket’s warhead and its unspent propellant, he said.

Hamas called Tuesday’s hospital blast “a horrific massacre” caused by an Israeli strike.

Islamic Jihad said Israeli orders issued days before for al-Ahli to be evacuated, and a previous strike at the hospital, proved the hospital was an target. The group added that the scale of the explosion, the angle of the explosive’s fall and the extent of destruction all pointed to Israel.

The Anglican bishop of Jerusalem, Hosam Naoum, said the hospital, run by the Episcopal Church, received at least three Israeli military orders to evacuate in the days before the blast. Israeli shelling hit it Sunday, wounding four staff, he said. Israel ordered all 22 hospitals in northern Gaza to evacuate last week. The Israeli military accuses the militants of hiding among civilians.

Hundreds of Palestinians had taken refuge in al-Ahli and other hospitals in Gaza City, hoping to be spared bombardment after Israel ordered all residents of the northern Gaza Strip to evacuate to the south.

On Wednesday morning, the blast scene was littered with charred cars. One man who had been sheltering there with his family, Mohammed al-Hayek, said he was sitting with other men in a hospital stairwell Tuesday night when he stepped away for coffee.

“When I returned, they were torn to pieces,” he said.

The death toll was in dispute. The Health Ministry initially said at least 500 had died, but revised that number to 471 on Wednesday. Al-Ahli officials said the toll was in the hundreds.

The Gaza Health Ministry said 3,478 people have been killed in Gaza since the war began, and more than 12,000 wounded, mostly women, children and the elderly. Another 1,300 people across Gaza are believed to be buried under the rubble, alive or dead, health authorities said.

More than 1,400 people in Israel have been killed, mostly civilians slain during Hamas’ deadly incursion. Militants in Gaza have launched rockets every day since toward cities across Israel.

Israel has been expected to launch a ground invasion into Gaza, though military officials say no decision has been made.

More than 1 million Palestinians have fled their homes — roughly half of Gaza’s population. Those fleeing the north and Gaza City to move south have crowded into U.N. schools or the homes of relatives.

With Israeli airstrikes relentlessly pounding the Gaza Strip, displaced Palestinians increasingly feel that no place is safe.

The Musa family fled to the typically sleepy central town of Deir al-Balah and took shelter in a cousin’s three-story home near the local hospital. But at 7:30 p.m. Wednesday, a series of explosions, believed to be airstrikes, rocked the building, turning the family home into a mountain of rubble that they said buried some 20 women and children.

The dead body of Hiam Musa, the sister-in-law of Associated Press photojournalist Adel Hana, was recovered from the wreckage Wednesday evening, the family said. They don’t know who else is under the rubble.

“It doesn’t make sense,” Hana said. “We went to Deir al-Balah because it’s quiet, we thought we would be safe.”

The Israeli military said it was investigating.

Debre and Nessman reported from Jerusalem. Associated Press journalists Amy Teibel in Jerusalem; Samya Kullab in Baghdad; Abby Sewell in Beirut; Samy Magdy and Jack Jeffrey in Cairo; and Ashraf Sweilam in el-Arish, Egypt, contributed to this report.