(NewsNation) — An explosion at Ahli Arab Hospital in Gaza City set off global outcry and led to the cancellation of diplomatic meetings between President Joe Biden — who is currently visiting Israel — and America’s Arab allies in the region.

But the cause of the explosion was not immediately clear. Palestinian sources on the ground pointed the finger at Israel, which has been bombarding the Gaza Strip since last week’s Hamas-led terror attack in Southern Israel.

But Israel denied responsibility for the attack, instead blaming a misfire of a rocket from the Palestinian militant group Islamic Jihad.

President Biden waded into that debate when he landed in Israel, telling reporters that the United States has concluded that it was likely “the other team” — meaning, not the Israeli military — that was responsible for the explosion.

During past conflicts between Israel and Gaza, the Pentagon has closely monitored the fighting; the Israeli military has historically been closely supplied by the United States.

When Biden was asked on Wednesday why he came to the conclusion he did, he pointed to “data I was shown by my Defense Department.”

A spokeswoman for the National Security Council cautioned that while they are continuing to collect information, their “current assessment” is that the blast was not caused by Israel. She based her conclusion off analysis from “overhead imagery, intercepts and open source information.”

Still, there has been no thorough investigation on the ground into the attack which would allow a more detailed forensic analysis. It’s also not clear how many people were killed in the attack. Initial reports of casualties following these kinds of events are often unreliable.