Arriving in Israel on Wednesday, U.S. President Joe Biden reaffirmed support for Israel’s fight against Hamas and confirmed its claim that militants were responsible for a blast that claimed a large number of Palestinian lives at a hospital in Gaza.

In addition to destroying White House preparations for Biden’s emergency diplomatic mission to the Middle East, the firestorm that destroyed the Al-Ahli al-Arabi hospital produced some of the most horrific images yet from the 12-day battle. Arab leaders also canceled their scheduled summit with the U.S. president.

Palestinian officials blamed an Israeli air strike for the blast, which it said had killed as many as 500 people. Israel said the blast was caused by a failed rocket launch by the Palestinian Islamic Jihad militant group, which denied blame.

Speaking alongside Israeli Prime Minister Benjamin Netanyahu, Biden said: “I was deeply saddened and outraged by the explosion of the hospital in Gaza yesterday, and based on what I’ve seen, it 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 world is looking. Israel has a value set like the United States does, and other democracies, and they are looking to see what we are going to do.”

Biden’s trip to the Middle East was supposed to calm the region, even as he demonstrated U.S. support for its ally Israel, which has vowed to annihilate the Hamas movement whose fighters killed 1,400 Israelis in a rampage on Oct. 7.