Images from al-Ahli Hospital on Wednesday morning showed a blackened hospital parking lot filled with burned-out cars. At the time of the attack, that parking lot and nearby courtyard were filled with hundreds of families sheltering near the hospital, according to first responders and aid groups.

“Because of the airstrikes everywhere else in Gaza, people left to take shelter in this hospital. Children, women, elders, patients, a huge number of people went to the hospital for refuge, following calls of evacuation and constant bombardment,” said Mahmoud Bassal, civil defense spokesperson in Gaza.

After Israel’s military ordered the full evacuation of Gaza City and northern neighborhoods last week, many civilians feared more intense waves of airstrikes on the area.

It’s unclear who is behind the al-Ahli hospital attack; Palestinian and Israeli officials are blaming each other. Israel’s military said that part of a “barrage of rockets” fired by the Islamic Jihad militant group erroneously hit the area. Hamas maintains an Israeli airstrike hit the site. Neither claim could be immediately verified by The Washington Post.

Hundreds of injured civilians were rushed to Gaza City’s main hospital, al-Shifa, where doctors reported having to treat the wounded on the hospital floor after running out of beds. Images from the scene showed men, women and children, many covered in dust and blood, crowding into the medical complex for treatment.

“The flood of victims and the [severity] of their injuries exceeds the capabilities of the medical teams and ambulances,” Gaza’s Health Ministry said in a statement posted to Facebook.

Video verified by The Washington Post captures the first sounds of an explosion — a whirring through the air and then a blast. The camera pans to show fire and orange plumes of smoke.

The attack prompted renewed calls from humanitarian organizations for the protection of civilians. Aid officials had been issuing increasingly dire warnings that a humanitarian catastrophe is unfolding in Gaza as Israel wages a devastating campaign of airstrikes against Hamas.

Hospitals in Gaza warned they were already running out of generator fuel, morgues were filling up and overstretched rescue workers reported they were unable to recover over 1,000 bodies from beneath buildings destroyed by airstrikes.

Medical infrastructure in Gaza has “entered the actual collapse phase,” according the Health Ministry statement. “The coming hours are dangerous for the future of health services provided to the sick and the wounded,” it said.

More than 10 hospitals have been damaged by airstrikes since war broke out between Hamas and Israel. Medical workers have also been killed in the violence. More than 3,400 people had been killed in Gaza and over 12,000 wounded, according to the Gaza Health Ministry, and nearly two-thirds of those killed were children.

Regional leaders also issued calls for an end to the conflict in Gaza. Jordan’s king warned the war “has entered a dangerous phase,” and “will plunge the region into an unspeakable disaster,” according to a palace statement.

President Biden arrived in Israel on Wednesday in what was supposed to be the first stop on a Middle East tour, but his itinerary began to unravel after mourning periods were announced for victims of the hospital attack.

Palestinian Authority President Mahmoud Abbas canceled his meeting with Biden in Amman alongside the leaders of Egypt and Jordan. Later in the evening, those leaders canceled their planned encounters with Biden as well.

George reported from Jerusalem, and Mahfouz reported from Cairo.