KHAN YOUNIS, Gaza Strip >> A massive blast rocked a Gaza City hospital packed with wounded and other Palestinians seeking shelter Tuesday, killing hundreds of people, the Hamas-run Health Ministry said. Hamas blamed an Israeli airstrike, while the Israeli military blamed a rocket misfired by other Palestinian militants.

At least 500 people were killed, the ministry said.

As rage spread through the region because of the hospital carnage, and with President Joe Biden heading to the Mideast in hopes of stopping the war from spreading, Jordan’s foreign minister said his country canceled a regional summit scheduled for Wednesday in Amman, where Biden was to meet with Jordan’s King Abdullah II, Palestinian President Mahmoud Abbas and Egyptian President Abdel Fattah el-Sissi.

The war between Israel and Hamas was “pushing the region to the brink,” Foreign Minister Ayman Safadi told state-run television. He said Jordan would host the summit only when everyone had agreed its purpose would be to “stop the war, respect the humanity of the Palestinians and deliver the aid they deserve.”

Biden will now visit only Israel, a White House official said.

The explosion at the al-Ahli Hospital left gruesome scenes. Video that The Associated Press confirmed was from the hospital showed fire engulfing the building and the hospital grounds strewn with torn bodies, many of them young children. The grass around them was strewn with blankets, school backpacks and other belongings.

The bloodshed unfolded as the U.S. tried to convince Israel to allow the delivery of supplies to desperate civilians, aid groups and hospitals in the tiny Gaza Strip, which has been under a complete siege since Hamas’ deadly rampage in southern Israel last week. Hundreds of thousands of increasingly desperate people were searching for bread and water.

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

The Israeli military blamed Islamic Jihad, a smaller, more radical Palestinian militant group that often works with Hamas. The military said Islamic Jihad militants had fired a barrage of rockets near the hospital and that “intelligence from multiple sources” indicated the group was responsible.

In a briefing with reporters, the chief army spokesman, Rear Adm. Daniel Hagari, said the army determined there were no air force, ground or naval attacks in the area at the time of the blast. He said radar detected outgoing rocket fire at the same moment, and intercepted communications between militant groups indicated that Islamic Jihad fired the rockets.

Hagari also shared aerial footage collected by a military drone that showed a blast that he said was inconsistent with Israeli weaponry. He said the explosion occurred in the building’s parking lot, and he noted that the death toll could not be confirmed.

Since the war began, the military said in a statement that roughly 450 rockets fired at Israel by militant groups had landed in Gaza, “endangering and harming the lives of Gazan residents.”

Islamic Jihad dismissed those claims, accusing Israel of “trying hard to evade responsibility for the brutal massacre it committed.”

The group pointed to Israel’s order that Al-Ahli be evacuated and its previous bombing of the hospital complex as proof that the hospital was an Israeli target. It also said the scale of the explosion, the angle of the bomb’s fall and the extent of the destruction all pointed to Israel.

Hundreds of Palestinians had taken refuge in al-Ahli and other hospitals in Gaza City in past days, hoping they would be spared bombardment after Israel ordered all residents of the city and surrounding areas to evacuate to the southern Gaza Strip.

Ambulances and private cars rushed some 350 casualties from the al-Ahli blast to Gaza City’s main hospital, al-Shifa, which was already overwhelmed with wounded from other strikes, said its director, Mohammed Abu Selmia. The wounded were laid onto bloody floors, screaming in pain.

“We need equipment, we need medicine, we need beds, we need anesthesia, we need everything,” Abu Selmia said. He warned that fuel for the hospital’s generators would run out within hours.

Before the al-Alhi Hospital deaths, Israeli strikes on Gaza killed at least 2,778 people and wounded 9,700, according to the Gaza Health Ministry, and nearly two-thirds of those killed were children. Another 1,200 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 who were slain in Hamas’ Oct. 7 attack. The assault also resulted in some 200 being taken captive into Gaza. Hamas militants in Gaza have launched rockets every day since, aiming at cities across Israel.

Hundreds of Palestinians flooded the streets of major West Bank cities including Ramallah, the seat of the Palestinian Authority, where protesters hurled stones at Palestinian security forces who fired back with stun grenades. Others threw stones at Israeli checkpoints, where soldiers killed one Palestinian, West Bank authorities said.

Elsewhere, hundreds of people joined protests that erupted in Beirut, Iraq and Amman, where an angry crowd gathered outside the Israeli Embassy.

In Amman, a palace statement said Jordan’s king condemned “the ugly massacre perpetrated by Israel against innocent civilians.”

The king “warned that this war, which has entered a dangerous phase, will plunge the region into an unspeakable disaster,” the statement said.

With tens of thousands of troops massed along the border, Israel has been expected to launch a ground invasion into Gaza, but its plans remained uncertain.

“We are preparing for the next stages of war,” military spokesman Lt. Col. Richard Hecht said. “We haven’t said what they will be. Everybody’s talking about a ground offensive. It might be something different.”

Throughout the day Tuesday, airstrikes killed dozens of civilians and at least one senior Hamas figure in the southern half of the Gaza Strip, where the Israeli military told fleeing Palestinians to go. An Associated Press reporter saw around 50 bodies brought to Nasser Hospital after strikes in the southern city of Khan Younis.

The Israeli military said it was targeting Hamas hideouts, infrastructure and command centers.

An airstrike in Deir al Balah reduced a house to rubble, killing a man and 11 women and children inside and in a neighboring house, some of whom had evacuated from Gaza City. Witnesses said there was no warning before the strike.

Shelling from Israeli tanks hit a U.N. school in central Gaza where 4,000 Palestinians had taken refuge, killing six people and wounding dozens, the United Nations Palestinian refugee agency said. At least 24 U.N. installations have been hit the past week, killing at least 14 members of the agency’s staff.

A barrage of strikes crashed into the Bureij refugee camp in central Gaza, leveling an entire block of homes and causing dozens of casualties, residents said. Among those killed was one of Hamas’ top military commanders, Ayman Nofal, the group’s military wing said. He is the highest-profile militant to have been killed in the war.

In Gaza City, Israeli airstrikes also hit the house of Hamas’ top political official, Ismail Haniyeh, killing at least 14 people. Haniyeh is based in Doha, Qatar, but his family lives in Gaza City. The Hamas media office did not immediately identify those killed.

Israeli Prime Minister Benjamin Netanyahu sought to put the blame on Hamas for Israel’s retaliatory attacks and the rising civilian casualties in Gaza. “Not only is it targeting and murdering civilians with unprecedented savagery, it’s hiding behind civilians,” he said.

With Israel barring entry of most water, fuel and food into Gaza since Hamas’ brutal attack, U.S. Secretary of State Antony Blinken secured an agreement with Netanyahu to discuss creation of a mechanism for delivering aid to the territory’s 2.3 million people. U.S. officials said the gain might appear modest, but stressed that it was a significant step forward.

Still, as of late Tuesday, there was no deal in place. A top Israeli official said his country was demanding guarantees that Hamas militants would not seize any aid deliveries. Tzahi Hanegbi, head of Israel’s National Security Council, suggested entry of aid also depended on the return of hostages held by Hamas.

More than 1 million Palestinians have fled their homes — roughly half of Gaza’s population — and 60% are now in the approximately 14-kilometer (8-mile) long area south of the evacuation zone, the U.N. said.

At the Rafah crossing, Gaza’s only connection to Egypt, truckloads of aid have been waiting to enter for more than a day. The World Food Program said it had more than 300 tons of food ready to cross into Gaza.

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