It wasn’t supposed to be that way.

Biden’s top diplomat, Antony Blinken, had spent the last week shuttling frenetically between seven countries in the hopes of forging a more unified position on the war in Gaza.

“I heard a lot of good ideas about some of the things we need to do,” Blinken told reporters in Cairo after meeting Egyptian President Abdel Fatah El-Sisi on Sunday

But any sense of public comity between Washington and its Arab partners was shattered on Tuesday as gruesome images emerged at the site of the Al-Ahli Anglican hospital in Gaza City. Palestinian authorities say an Israeli airstrike killed an estimated 500 people in the attack. Israel denies the charge, saying the facility was blown up by errant rocket fire from an Islamist militant group. The White House, citing preliminary U.S. intelligence, has sided with Israel.

At stake are urgent issues related to the Gaza war that require allied cooperation, including coordinating the safe passage of U.S. citizens out of Gaza; securing a humanitarian aid corridor to besieged Palestinians; freeing American hostages from Hamas; and preventing Iran or Hezbollah from opening a second front against Israel.

The hospital blast has “derailed a much-needed opportunity to make meaningful progress on the near-term solution to the Gaza crisis,” said Suzanne Maloney, director of foreign policy at the Brookings Institution. “And by inflaming opinion across the Arab world, it has heightened prospects for escalation and a much more dangerous and protracted conflict in the region.”

Shortly after the explosion on Tuesday, Palestinian Authority President Mahmoud Abbas canceled his scheduled meeting with Biden, a move that caught U.S. officials by surprise and immediately raised concerns that Biden’s entire Arab itinerary was in jeopardy.

U.S. officials sought to confirm with Abbas that the meeting could not be put back on the schedule, and Blinken phoned the Palestinian leader “to express profound condolences for the civilian lives lost in the explosion,” said State Department spokesman Matt Miller.

But the damage was done, and Jordanian King Abdullah, who had planned to host a four-way summit with Biden, Abbas and Sisi, canceled the entire event, calling the explosion an “ugly massacre perpetrated by Israel against innocent civilians.”

“This was a heinous war crime that cannot be ignored,” he said.

In Israel, Biden lent his credibility to the Israeli claim of Palestinian fault, saying “Based on what I’ve seen it looks like it was the other team, not you.”

When asked what made him think that, Biden cited the “data I was shown by my Defense Department,” without elaborating. The National Security Council later issued a statement attributing the U.S. intelligence assessment to “overhead imagery, intercepts and open source information,” though so far it has not publicly disclosed any of those materials.

A Hamas representative shot back, saying Biden’s remarks proved the United States was “blindly biased toward the Israeli occupation.”

During his stops in Israel, Biden met with families impacted by Hamas’s attacks and public billboards thanked him for his support.

As he felt the warm embrace of Israeli society, protests continued to build throughout the Muslim world, which has long objected to the billions of dollars of military aid the U.S. sends to Israel every year.

In Jordan, where Blinken had been meeting with Arab officials to prepare for Biden’s visit, protesters stormed the Israeli embassy and threw rocks at it before police shot tear gas and moved them away from the building.

“They want to kill all the people of Gaza,” said Sohaib, a 27-year-old graphic designer who said he came to protest outside the embassy to express his disgust with the governments of Israel and the United States.

Another protester, who declined to give his name, said Washington’s unwavering support for Israel was infuriating Jordan’s youth population, pointing to a crowd of young men demonstrating against Israel’s treatment of Palestinians.

“You can see they are all young and they hate America today,” he said.

Even before the hospital explosion, thousands of Jordanians took to the street, expressing solidarity with Palestinians and chanting pro-Hamas slogans. “They said Hamas is a terrorist; all of Jordan is Hamas,” hundreds thundered during a protest last week.

“The situation in Jordan is especially dangerous,” said Bruce Riedel, a Middle East scholar who previously served in senior positions at the CIA. “The peace treaty with Israel is extremely unpopular. Demonstrations against the Israeli embassy in Amman could escalate into a challenge to national stability.”

In Egypt, Sisi condemned what he called the “intentional bombing” by Israel that “represents a violation of international law.” The U.S. embassy put out a notification to American travelers warning them to avoid protests related to the conflict.

In the West Bank, Palestinian security forces shot stun grenades and tear gas to break up protesters demonstrating against Abbas, who is widely unpopular among Palestinians.

Despite their public effort to create distance with the United States, Sisi, Abbas and Abdullah had a significant impact on Blinken’s approach to the Gaza war in the days leading up to Biden’s visit.

The United States switched, for instance, its policy seeking safe passage for Palestinian civilians through Egypt in response to meetings with Abbas and Sisi, who opposed the proposal out fear that fleeing Palestinians may never be able to return to Gaza. Instead, he Biden administration has embraced the idea of establishing safe areas inside Gaza.

“I’ve heard directly from Palestinian Authority President Abbas and from virtually every other leader that I’ve talked to in the region, that that idea is a nonstarter,” Blinken told al-Arabiya on Sunday.

Another message U.S. officials took to heart from Arab leaders was that a humanitarian collapse in Gaza could stoke popular sentiment and potentially destabilize their own countries — a prediction that now appears prescient.

Their focus on the aid is one of the reasons Blinken and his team engaged in a nearly 8 hour negotiating session with Israel’s war cabinet this week in an effort to forge an agreement on humanitarian aid access.

That led up to what Biden announced on Wednesday: an agreement with Israel to allow the delivery of aid on condition that there will be inspections and that the aid won’t go to Hamas. “Israel agreed the humanitarian assistance can begin to move,” Biden said.

But a critical player on aid delivery is Egypt, which control part of the Rafah border crossing, and Hamas, which controls the other half. That is why Arab leaders, who have communication links with Hamas and other key players on the ground, were viewed as a critical part of Biden’s trip.

“The cancellation of Biden’s trip to Jordan is a setback for efforts to find a diplomatic solution to the worsening crisis in the region,” said Riedel. “It reinforces unintentionally the perception that America doesn’t care about Arab and Muslim voices.”

Sarah Dadouch, in Beirut, Tyler Pager, in Tel Aviv, Claire Parker, in Cairo, and Miriam Berger, in Ramallah, contributed to this report.