US President Joe Biden has been speaking to Israeli Prime Minister Benjamin Netanyahu in a televised conversation after his arrival in Tel Aviv.

Biden said questions needed to be answered about the explosion at a hospital in Gaza. He indicated that Washington was leaning toward the theory offered by Israel that it had been caused by a misfired rocket from the militant group Islamic Jihad.

"I was deeply saddened and outraged by the explosion in Gaza yesterday. "Based on what I've seen, it appears that it was done by the other team, not you."

However, Biden said there were "a lot of people out there" who were unsure about the cause of the blast.

Biden also paid tribute to the people of Israel.

"Their courage their commitment their bravery is stunning, I am proud to be here," he said.