The Hamas-controlled Gaza authorities said it was an Israeli airstrike. Israel pointed the finger at a failed missile from militant group Palestinian Islamic Jihad. The US called for an investigation.

Blaming Israel for what they called an attack, the leaders of Jordan, Egypt and the Palestinian Authority canceled a summit with Biden that had been scheduled for Wednesday in Amman. Anti-Israel protests broke out in several major cities around the region. 

Biden had planned to use the trip to reinforce the US commitment to Israel as it readies what’s expected to be a punishing ground incursion to eradicate Hamas from Gaza. He also intended to send a warning to Iran and its allies not to follow through on threats to attack Israel from the north.

Even before the hospital tragedy, the US had been pressing Prime Minister Benjamin Netanyahu to do more to limit civilian casualties and ease the spiraling humanitarian crisis in Hamas-controlled Gaza. Israel has vowed to obliterate the group after its Oct. 7 attacks, which killed 1,300 Israelis. Since then, Israeli airstrikes have killed more than 3,000 Gazans.

“The optics are going to be very bad,” said Randa Slim, senior fellow and director of conflict resolution at the Middle East Institute in Washington. After the hospital blast, she said, “People are up in arms. It’s going to be very hard especially if Biden is to come to Israel and repeat the mantra that Israel has the right to defend itself.”

The White House said the Jordan meeting would be rescheduled for a later date, citing the days of mourning for the hospital blast declared by Palestinian Authority leader Mahmoud Abbas. Later, Biden spoke by telephone with Jordan’s King Abdullah II and Netanyahu, the White House said, without providing further details.

“I am outraged and deeply saddened by the explosion at the Al Ahli Arab hospital in Gaza, and the terrible loss of life that resulted,” Biden said in a statement on Tuesday night. “The United States stands unequivocally for the protection of civilian life during conflict and we mourn the patients, medical staff and other innocents killed or wounded in this tragedy.” 

Even before the explosion, officials in the US and the region were increasingly worried that they wouldn’t be able to keep the conflict from spreading once Israel goes ahead with the ground invasion. Biden has already sent two aircraft carriers to the region and put troops on alert to send a message of deterrence to Iran and its ally Hezbollah, whose thousands of missiles could pose a severe threat to Israel. 

“The whole region is at the brink of falling into the abyss that this new cycle of death and destruction is pushing us towards,” the Jordanian king said after a meeting in Berlin with German Chancellor Olaf Scholz earlier Tuesday. “The threat of this war expanding is real.”

Fighting picked up with Hezbollah across Israel’s northern border with Lebanon – the group said five of its fighters were killed in clashes Tuesday – and Tehran warned this week that a wider war is becoming “inevitable.”

Administration officials have said they didn’t plan to deploy the US military on the ground in Israel. But an escalation raises the risk of a miscalculation, such as an errant missile hitting US forces in the Mediterranean, or a broad assault on Israel, that could force an American response. The US also still has about 2,500 troops in Iraq, where Iranian-backed militias pose a major military threat. Biden called the Iraqi prime minister Tuesday to discuss how to prevent an expansion of the Israel-Hamas conflict.

The hospital attack casts a shadow over a trip the White House had hoped would showcase Biden’s commitment to a key ally and his foreign-policy experience, key themes as he heads into next year’s election campaign. 

Late Tuesday, Israeli leaders renewed their vow to destroy Hamas, which the US and European Union have designated a terrorist group. But the 2 million civilians who live in Hamas-controlled Gaza have nowhere to go with the borders closed and Israel cutting off electricity and supplies and stepping up air attacks.

Egypt and Jordan say they won’t accept refugees from Gaza, leaving unresolved the question of where civilians there can go. Some Israeli officials have suggested Gazans, too, bear responsibility for Hamas’s actions, having elected the group to power nearly two decades ago. 

But Biden has rejected that, pointedly warning Israel last week that civilians in Gaza can’t be held responsible. Adding to the tension are more than 500 US citizens now trapped there, as well as 13 American hostages held by Hamas there after the Oct. 7 attack. 

Secretary of State Antony Blinken, after a whirlwind tour of the region and nine hours of talks with Israel officials Monday, announced the US and Israel would work on a deal to get aid to Gaza. But on Tuesday, trucks were still stuck at the border as Israel sought guarantees the aid wouldn’t be diverted to Hamas. There was no sign of progress in efforts to allow at least foreign citizens to leave Gaza.

Scholz, the German chancellor, said he underlined the need for aid in his meeting with Netanyahu in Israel on Tuesday, though there were no new public commitments. Biden’s brief visit may at least buy Gazans that much time before a ground invasion.

Israeli officials focus on the US messages of support. Security officials say American visitors, from Defense Secretary Lloyd Austin last week to Central Command Commander General Michael “Erik” Kurilla, in Israel on Tuesday, have shown strong support for their plan to eliminate Hamas, and Biden will do the same.

One senior military official, who spoke on condition of anonymity, said the Americans have sought to offer perspective and to ensure that the Israelis know the implications of their actions, but the military aid is not conditioned on their taking the advice.

Adding to Israel’s confidence is the conviction that it has the tacit support of some major Arab countries for its plan to destroy Hamas, though they can’t admit that publicly, the official said.