American and Israeli officials said their intelligence showed that the deadly blast at a Gaza hospital on Tuesday was caused by an armed Palestinian group, rebutting Palestinian claims that an Israeli strike caused the explosion.
The U.S. officials, who spoke on condition of anonymity to discuss the sensitive information, said they were basing their early analysis on multiple strands of intelligence indicating that the blast at Ahli Arab hospital was caused by Palestinian Islamic Jihad, a group allied with Hamas. The group said Israel’s accusations that one of its rockets malfunctioned and hit the hospital were “false and baseless.” Hamas has not provided any documentation of Israeli involvement.
The officials cautioned that the analysis was preliminary and that they were continuing to collect and analyze evidence. Neither side’s claims about who was responsible have been independently verified.
The American intelligence, first mentioned by President Biden, includes satellite and other infrared data showing a launch of a rocket or missile from Palestinian fighter positions within Gaza. American intelligence agencies have also analyzed open-source video — recordings collected by journalists and others — of the launch showing that it did not come from the direction of Israeli military positions, the officials said. Israeli officials have also provided the United States with intercepts of Hamas officials saying the strike came from forces aligned with Palestinian militant groups.
“The U.S. government assesses that Israel was not responsible for an explosion that killed hundreds of civilians yesterday at the Al Ahli Hospital in the Gaza Strip,” said Adrienne Watson, a spokeswoman for the National Security Council. “Our assessment is based on available reporting, including intelligence, missile activity and open-source video and images of the incident.”
Ms. Watson said the intelligence indicated that some Palestinian fighters in the Gaza Strip believed the explosion was likely caused by an errant rocket or missile launch carried out by Palestinian Islamic Jihad. “The militants were still investigating what had happened. We continue to work to corroborate whether the explosion resulted from a failed P.I.J. rocket,” she said.
U.S. officials cautioned, however, that the full story of what happened at the hospital is not known. While they do not believe an Israeli strike caused the attack, they are uncertain about how an errant Palestinian rocket could have caused so much loss of life at the hospital.
The main hospital building did not sustain critical damage. While there was light damage to the roofs of the two buildings near the main building, both structures remain intact. It is possible that a rocket hit a parking lot near the hospital where people were gathered, but American officials are trying to learn more.
The efforts by U.S. and Israeli officials to explain their findings came as protests over the Gaza hospital explosion spread across the Middle East, bringing defiant crowds to embassies and consulates of countries that demonstrators said were complicit in the humanitarian crisis.
Multiple officials said the evidence gathered so far refuted claims that Israeli forces were responsible for the blast, and it was strong enough for Mr. Biden to make comments supporting Israel’s account of events.
“Based on what I’ve seen, it appears as though it was done by the other team, not you,” Mr. Biden told Prime Minister Benjamin Netanyahu of Israel during a joint appearance on his rare wartime visit to Israel. Mr. Biden said later that he had based his comments on an American military evaluation.
A senior Defense Department official said based on the launch data collected by infrared sensors that the United States was “fairly confident” the launch did not come from Israeli forces.
The Israel Defense Forces said its finding that a malfunctioning rocket fired by Palestinian Islamic Jihad had caused the blast came after a review of evidence. The group has denied the claim, and the Hamas-run Gazan health ministry said that an Israeli strike caused the blast, which it said killed hundreds of Palestinians. (The death toll could not be independently confirmed, though video footage verified by The New York Times showed scores of bodies in the hospital’s courtyard, suggesting the number of victims was high.)
In a press briefing on Wednesday morning, Rear Adm. Daniel Hagari, an Israeli military spokesman, said that Islamic Jihad fired 10 rockets at 6:59 p.m. local time. One of the rockets, he said, fell to earth prematurely, hitting a parking lot outside the hospital. He said that Israel had not fired any ordnance in the area of the hospital at that time.
He cited a photograph of the parking lot that was posted on social media on Wednesday morning that he said did not show the kind of impact that would have been caused by an Israeli missile. The New York Times has not verified the photo. The photo shows the effects of a fire — burned-out cars and scorched ground. Admiral Hagari said that the damage was caused by rocket fuel that caught fire after hitting the ground.
He also showed aerial footage that he said was taken from a military drone overnight. In the images, he said, there was no evidence of a crater caused by an Israeli missile.
And he dismissed suggestions that the strike was caused by an errant Israeli air defense interceptor. He said Israel does not fire air defense missiles into Gazan airspace.
On Tuesday, Israeli officials provided American intelligence agencies with the intercepted communications.
U.S. officials said their assessment was not based only on the Israeli intercepts. American officials spent the night analyzing those intercepts along with the open-source data, videos captured by journalists and others that show a rocket flying in the vicinity of the hospital.
Senators Mark Warner, Democrat of Virginia, and Marco Rubio, Republican of Florida, who lead the Senate Intelligence Committee, said on Wednesday that the committee had reviewed the intelligence and also attributed the blast to a failed Palestinian rocket launch.
The United States regularly uses infrared satellite collection to analyze launches. The warning system was one of the first pieces of intelligence that showed that a Malaysia Airlines plane was shot down by Russian forces over Ukraine in 2014.