A day after a deadly blast tore through Al-Ahli Baptist Hospital in Gaza, sparking protests across the region, the United States has released its own assessment of what caused the devastation.
Israel has laid out evidence that it said shows a misfire by militant group Islamic Jihad caused the blast, and US President Joe Biden on Wednesday backed that explanation, citing US intelligence. A spokesperson for the National Security Council later said that analysis of overhead imagery, intercepts and open-source information suggested that Israel is "not responsible."
Palestinian officials and several Arab leaders nevertheless accuse Israel of hitting the hospital amid its ongoing airstrikes in Gaza. Islamic Jihad -- a rival group to Hamas -- has denied responsibility.
Hundreds are believed to have died in the attack, according to the Hamas-controlled Health Ministry in Gaza, and images of the bloody aftermath have spurred protests across the region.
Here's a look at what we know -- and don't know -- so far.
What happened at the hospital?
Video of the moment of the blast at the Al-Alhi Baptist Hospital, geolocated by CNN, shows the sky light up as a large explosion erupts on the hospital grounds, sending a cloud of flame and smoke into the air.
In the building, there was panic. Dr. Fadel Na'eem, head of the orthopedic department, said he was performing surgery when a deafening blast sounded through the hospital. He said panic ensued as staff members ran into the operating room screaming for help and reporting multiple casualties.
He told CNN in a recorded video: "I just finished one surgery and suddenly we heard a big explosion, we thought it's outside the hospital because we never thought that they would bomb the hospital."
After he left the theater, Dr. Na'eem said he found an overwhelming scene. "Many people were beheaded. Everywhere there was a big fire," he said. "The medical team scrambled to tend to the wounded and dying, but the magnitude of the devastation was overwhelming. The number was big and huge that we can't do anything."
While it is difficult to independently confirm how many people died in the blast, but the bloodshed could be seen in images from the aftermath shared on social media. In photos and videos, young children covered in dust are rushed to be treated for their wounds. Other bodies lay lifeless on the ground.
The Ministry of Health in Gaza has said the death toll is over 400.
What the Israelis and Palestinians have said
Palestinian officials blamed Israel for the attack on Tuesday evening.
Israeli Defense Forces (IDF) spokesperson Jonathan Conricus told CNN on Wednesday that the "first packet of information" was "evidence that clearly supports the fact that it could not have been an Israeli bomb."
Israel says that its intelligence shows a "failed rocket launch" by the Islamist militant group Islamic Jihad group was responsible. The Islamic Jihad movement denied those assertions as "false and baseless."
The IDF also released audio that it claimed captured a conversation between two Hamas operatives in which they spoke of a rocket launch from a cemetery near the hospital. According to an IDF translation of the conversation, one of the alleged operatives says: "They are saying that the shrapnel of the missile is local shrapnel and not like the Israeli shrapnel."
CNN cannot verify the authenticity of the recordings.
On Tuesday, the IDF presented imagery that it says proves the destruction at the hospital could not have been the result of an airstrike, saying there were no visible signs of craters or significant damage to buildings that would result from such a strike.
A video posted by the official State of Israel's account on social media platform X on Tuesday night was also presented as evidence that the hospital was struck in outgoing rocket fire from militants. But the timestamp on the video appeared not to match up with the time that the explosion took place, and the tweet was later edited to remove the video.
Israel Foreign Ministry spokesperson Lior Haiat told CNN: "We received the video, we thought it was from an official source but when we contacted him he said he got it from somewhere else, so we took it off."
On Wednesday, officials in Gaza also claimed that the Al-Ahli Baptist Hospital was damaged by two Israeli shells four days ago, after which the IDF warned the hospital's management to evacuate the premises. CNN has reached out to the IDF for comment on the claim.
What US intelligence suggests
The US government currently assesses that Israel "was not responsible" for the blast, according to the US National Security Council (NSC).
Biden, who was making a high-stakes visit to Israel on Wednesday, told Israeli Prime Minister Benjamin Netanyahu that the damage at the hospital "appears as though it was done by the other team, not you."
"But there's a lot of people out there not sure, so we've got a lot -- we've got to overcome a lot of things," Biden added.
The NSC on Wednesday afternoon leaned further into its assessment: "Intelligence indicates that some Palestinian militants in the Gaza Strip believed that the explosion was likely caused by an errant rocket or missile launch carried out by Palestinian Islamic Jihad (PIJ). The militants were still investigating what had happened," spokesperson Adrienne Watson said.
Officials told CNN separately that the initial evidence gathered by the US intelligence community suggests that the hospital strike came from a rocket launched by the Palestinian Islamic Jihad group.
Among the evidence is a blast analysis that suggests it was a ground explosion rather than an airstrike that hit the hospital, one of the sources said. There was no singular crater suggesting there was a bomb, but there was extensive fire damage and scattered debris that is consistent with an explosion starting from the ground level, according to the source.
That analysis is one data point that's led intelligence officials to lean toward assessing that the attack on the hospital was a rocket launch gone wrong.
Still, the blast analysis is just one of the things being examined by the intelligence community, which has surged intelligence collection assets to the region.
How has the world reacted?
A number of countries have expressed horror at the loss of life at the hospital, and urged caution in attributing blame until the circumstances become clear.
The United Nations has called for a careful investigation. Until independent investigators are able to assess the incident in detail, it is unlikely that the world will know with certainty what led to the blast.
Israel has provided the US with intelligence it has gathered related to the deadly Gaza hospital explosion, according to an Israeli official and another source familiar with the matter.
Several Arab countries, including Saudi Arabia, Jordan, Egypt, the United Arab Emirates and Iraq issued statements condemning Israel and accusing its military of bombing the hospital.
Meanwhile, thousands of protesters shouting anti-Israel slogans gathered in Lebanon, Iraq, Jordan, Kuwait, Egypt, and Tunisia. Protests also rocked the occupied West Bank city of Ramallah.