The president visited Israel and reiterated his commitment to the country’s security, adding that a blast at a Gaza hospital appeared to have been caused by a misfired rocket.President Joe Biden weighed in – cautiously – on a high-stakes question of who was responsible for the deadly explosion at a Gaza hospital, telling Israeli Prime Minister Benjamin Netanyahu that it appears "the other team" was to blame.

“The point is, is that 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 said at the top of a meeting with Netanyahu in Tel Aviv.

The Tuesday explosion killed hundreds and led to immediate condemnations of Israel by the Arab world, which accused the Israeli government of brutal retaliation after Hamas, a designated terrorist group, launched a massive attack on Israel earlier this month. Israel quickly denied responsibility, saying the lack of structural damage at the hospital means it could not have been an air attack.

Saudi Arabia, Jordan, Iraq, Egypt and the United Arab Emirates issued statements denouncing Israel for the attack, while people demonstrated in the streets across the Arab world and in the West Bank city of Ramallah. Hours before Biden boarded Air Force One for the region, Jordan canceled a meeting the American president was to have with leaders of Jordan, the Palestinian Authority and Egypt, limiting Biden's diplomatic mission even before he arrived.

But as the hours unfolded, it became less clear who was to blame for the explosion. Israel pointed to video taken by Al Jazeera that it said revealed a "failed rocket launch" by Islamic Jihad militants.

Gaza has been awaiting a counterattack by Israel, which is determined to eradicate Hamas. But it also would be very risky for Israel to launch a deliberate attack on a civilian target just as Biden – who has repeatedly said the United States stands by Israel – was leaving for the region for talks.

Biden is facing an enormous and high-stakes test of his diplomatic skills, as he attempts to keep the crisis from escalating and expanding elsewhere in the region.

John Kirby, the National Security Council spokesman, told reporters aboard Air Force One that Biden would ask “tough questions” of the Israelis about their intentions in the coming weeks. Kirby said humanitarian assistance would be a focus of the conversations but declined to detail any potential announcements about humanitarian aid.

As for the hospital explosion, Kirby said Biden had directed his national security staff "to gather as much information and context as possible so that we can learn more about how this happened."

Netanyahu – who has had a chilly relationship with Biden that goes back to the Israeli leader's opposition to the Iran nuclear deal brokered when Biden was vice president – thanked the American president for coming, noting that it was the first time a U.S. president visited Israel at war.

“This will be a different kind of war because Hamas is a different kind of enemy,” Netanyahu said. "Hamas wants to kill as many Israelis as possible."

The Israeli leader said "Israel will do everything it can to keep civilians out of harm's way," but that “the road to victory will be long and hard.”

Biden called the Hamas attack "brutal" and "almost beyond belief,” telling Netanyahu that "you’re not alone. … We will continue to have Israel’s back as you work to defend your people."

“We will continue to work with you and partners across the region to prevent more tragedy,” Biden said.