TEL AVIV — President Biden vowed to show the world that America stands in solidarity with Israelis during his visit to that country Wednesday, and offered an assessment that the deadly explosion at a Gaza Strip hospital apparently was not carried out by the Israeli military.

“Based on what I’ve seen, it appears as though it was done by the other team, not you,” Mr. Biden told Prime Minister Netanyahu during a meeting. Yet Mr. Biden lamented that there were “a lot of people out there” who weren’t sure what caused the blast.

Mr. Biden didn’t offer details on why he believed the blast was not caused by the Israelis. The Hamas-run Gaza Health Ministry claimed that an Israeli airstrike caused the destruction and hundreds of deaths. 

The Israeli military denied involvement and presented an extraordinary amount of intelligence — including tracking of the rocket’s ascent from Gaza and its descent at the hospital and radio and video interceptions — proving that the blast was caused by a misfired rocket from the Palestinian Islamic Jihad, another Iranian proxy group. That organization denied responsibility.

Mr. Biden had been scheduled to visit Jordan to meet with Arab leaders after the stop in Israel, but the summit was called off after the hospital explosion. His remarks spoke both of the horrors the Israelis had endured, but also the growing humanitarian crisis for Palestinian civilians in Gaza.

He told Mr. Netanyahu he was “deeply saddened and outraged” by the hospital explosion. He stressed that “Hamas does not represent all the Palestinian people. and it has brought them only suffering.”

Mr. Biden spoke of the need to find ways of “encouraging life-saving capacity to help the Palestinians who are innocent, caught in the middle of this.”

Yet he also said Hamas had “slaughtered” Israelis in the October 7 attack that killed 1,400 people. Mr. Biden described at length the horror of the killing of innocent Israelis, including children.

“Americans are grieving, they really are,” Mr. Biden said. “Americans are worried.”

Mr. Netanyahu thanked Mr. Biden for coming to Israel, telling him the visit was “deeply, deeply moving.”

“I know I speak for all the people of Israel when I say thank you Mr. President, thank you for standing with Israel today, tomorrow and always,” he said.

Mr. Netanyahu said Mr. Biden had rightly drawn a clear line between the “forces of civilization and the forces of barbarism,” saying Israel was united in its resolve to defeat Hamas.

“The civilized world must unite to defeat Hamas,” he said.

Mr. Biden also planned to meet Israeli first responders and the families of victims and hostages. Mr. Netanyahu met Mr. Biden at Ben Gurion Airport and the two embraced. It was almost exactly a month ago that they sat together at the United Nations General Assembly, where Mr. Netanyahu marveled that a “historic peace between Israel and Saudi Arabia” seemed within reach.

The possibility of improved relations between Israel and its Arab neighbors appears to be on hold; Israel has been preparing for a potential ground invasion of Gaza in response to Hamas’s attacks.

Roughly 2,800 Palestinians have been claimed by Hamas’ health ministry in Gaza to have been killed by Israeli strikes in Gaza, although the Israeli military reports that more than 450 Hamas rockets have misfired in Gaza in this fighting alone and may have caused many of the casualties among Palestinian Arabs.

Another 1,200 people are believed to be buried under the rubble, alive or dead, Hamas health authorities claimed. Those numbers predate the explosion at the Al-Ahli hospital on Tuesday. 

Protests swept through the region after the blast at the hospital, which had been treating wounded Palestinians and sheltering many more who were seeking a refuge from the fighting.

Hundreds of Palestinians flooded the streets of major West Bank cities including Ramallah. More people joined protests that erupted at Beirut, Lebanon, and Amman, Jordan, where an angry crowd gathered outside the Israeli Embassy.

Outrage scuttled Mr. Biden’s plans to visit Jordan, where King Abdullah II was to host meetings with the Palestinian president, Mahmoud Abbas, and President el-Sissi of Egypt. Yet Mr. Abbas withdrew in protest, and the summit was subsequently canceled outright.

Jordan’s foreign minister, Ayman Safadi, told a state-run television network that the war is “pushing the region to the brink.”

Jordan declared three days of mourning after the hospital explosion and Mr. Safadi said the summit was canceled after speaking with all leaders. He said they had wanted the meeting to produce an end to the war, which seems unlikely now, and to give Palestinians the respect they deserve. 

A White House spokesman, John Kirby, said Mr. Biden understood the move was part of a “mutual” decision to call off the Jordan portion of his trip. He said Mr. Biden would speak to the Arab leaders by phone as he returned to Washington.

There are also fears that a new front could erupt along Israel’s northern border with Lebanon, where Hezbollah operates. The Iran-backed organization has been skirmishing with Israeli forces.

Always a believer in the power of personal diplomacy, Mr. Biden’s trip will test the limits of American influence in the Middle East at a volatile time. It’s his second trip to a conflict zone this year, after visiting Ukraine in February to show solidarity with the country as it battles a Russian invasion.