Seated alongside Prime Minister Benjamin Netanyahu in Israel on Wednesday, President Biden backed Israel's denial of responsibility for an explosion at a hospital in Gaza City, and expressed the United States' unwavering support for the Jewish people. 

Hamas has blamed Israel, while Israel has vehemently denied any involvement and says a rocket misfire from the group Islamic Jihad is to blame. Exactly what did happen has not been independently verified. Officials in the Hamas-run territory say the blast killed hundreds of people, but no death toll has been verified, and emerging images of the hospital in daylight suggest it was not leveled. 

"I'm deeply saddened and outraged by the explosion at 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," Mr. Biden said to Netanyahu and reporters in Tel Aviv. "But there's a lot of people out there who are not sure. So — we've got to overcome a lot of things."

Reporters later asked the president what made him confident the Israelis weren't behind the hospital strike. 

"The data I was shown by my Defense Department," he responded. 

Mr. Biden was on the ground in Israel for just a few hours Wednesday in an effort to show U.S. solidarity with Israel, and navigate a complicated situation with one of the United States' strongest allies. He was scheduled to visit Jordan next to visit with Arab leaders, but that portion of the trip was scrapped after Jordan's foreign minister said the summit was canceled. 

"I come to Israel with a single message — you're not alone," the president said in remarks at the conclusions of his meetings. "You are not alone. As long as the United States stands, and we will stand forever, we will not let you ever be alone. Most importantly, I know the recent terrorist assault on the people of this nation has left a deep, deep wound. More than 1,300 innocent Israelis killed, including at least 31 American citizens, by the terrorist group Hamas."

The attack on Oct. 7, the deadliest day for the Jewish people since the Holocaust, Mr. Biden said, has resurfaced painful scars.

"It has brought to the surface painful memories and scars left by millennia of antisemitism and the genocide of the Jewish people," Mr. Biden said. "The world watched then. It knew. And the world did nothing. We will not stand by and do nothing again. Not today, not tomorrow, not ever." 

Mr. Biden met with Israeli first responders and families of the victims, expressing his longtime support for Israel. 

"You don't have to be a Jew to be a Zionist," Mr. Biden said. 

Israel, he said, must again be a safe place for the Jewish people.

"The state of Israel was born to be a safe place for the Jewish people of the world," Mr. Biden said. "That's why it was born. I've long said if Israel didn't exist, we'd have to invent it. While it may not feel that way today, Israel must again be a safe place for the Jewish people. And I promise you, we're going to do everything in our power to make sure it will be. Seventy-five years ago, just 11 minutes after its founding, President Harry S. Truman and the United States of America became the first nation to recognize Israel. We've stood by your side ever since. We're going to stand by your side now." 

Americans are still missing in the conflict, some of them believed to be held by Hamas. The president spoke with the families of missing Americans on Friday. 

"You are not alone," the president said on Wednesday, saying there is "no higher priority" for him than their freedom. 

Seated alongside Netanyahu, Mr. Biden assured him that the U.S. will provide for Israel's defense. He also sought to distinguish Hamas from many of the Palestinian people. The president said Hamas is committing atrocities "that make ISIS look somewhat more rational." 

"And we have to also bear in mind that Hamas does not represent all the Palestinian people and has brought them only suffering," the president said. 

—Willie Inman contributed to this report.

In:
• Israel
• Joe Biden

Kathryn Watson

Kathryn Watson is a politics reporter for CBS News Digital based in Washington, D.C.