Health officials in Gaza say hundreds of people were killed in a huge blast Tuesday at a hospital in Gaza City, and Israeli and Palestinian officials traded accusations over who was responsible for the devastating explosion.

Palestinian officials blamed an Israeli airstrike and said at least 500 people were killed in the attack at the Al-Ahli Baptist Hospital in Gaza City. 

Israeli officials said they did not target a hospital and that their intelligence review indicated the blast was caused by a rocket launched by the militant group Islamic Jihad towards Israel that fell short.

Thousands of people were displaced or injured, said the Gaza Health Ministry. Hamas called it "a horrific massacre."

The head of the World Health Organization tweeted: "@WHO strongly condemns the attack on Al Ahli Arab Hospital in north Gaza. Early reports indicate hundreds of deaths and injuries. We call for the immediate protection of civilians and health care, and for the evacuation orders to be reversed."

"Words fail me," U.N. human rights chief Volker Türk said in a statement. "Tonight, hundreds of people were killed – horrifically – in a massive strike at Al Ahli Arab Hospital in Gaza City, including patients, healthcare workers and families that had been seeking refuge in and around the hospital." 

"We don't yet know the full scale of this carnage, but what is clear is that the violence and killings must stop at once. All States with influence must do everything in their power to bring an end to this horrendous situation," Türk said. "Those found responsible must be held to account."

Soon after the blast, Israeli officials disputed accusations that Israel had conducted the strike.

"An analysis of the IDF operational systems indicates that a barrage of rockets was fired by terrorists in Gaza, passing in close proximity to the Al-Ahli Al-Mahdi hospital in Gaza at the time it was hit," Israel Defense Forces spokesperson Rear Admiral Daniel Hagari said in a video statement. 

The Israeli military later posted a video it said showed rockets being launched from inside Gaza, failing to reach Israel, and instead striking the hospital. 

RAW FOOTAGE: A rocket aimed at Israel misfired and exploded at 18:59—the same moment a hospital was hit in Gaza. pic.twitter.com/Kf5xJazSap

— Israel Defense Forces (@IDF) October 17, 2023

Neither side's claims have been independently verified. 

President Biden said in a statement that he was "outraged and deeply saddened by the explosion at the Al Ahli Arab hospital in Gaza, and the terrible loss of life that resulted."

He said the United States "stands unequivocally for the protection of civilian life during conflict," and that he has directed his national security team to "continue gathering information about what exactly happened."

Mr. Biden traveled to Israel for a visit Wednesday, and after meeting there with Prime Minister Benjamin Netanyahu and other leaders, he said the evidence he has seen indicates Israel was not to blame.

"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 had been scheduled to meet with Arab leaders in Jordan after his Israel top, but they canceled on Tuesday. Palestinian Authority President Mahmoud Abbas announced he was returning to Ramallah from Amman due to the protests and concerns of violence in the West Bank.

Protests outside Israeli and U.S. embassies and consulates broke out in several countries after the hospital blast.

–Pamela Falk and Kathryn Watson contributed reporting.

In:
• Hamas
• Israel
• Gaza Strip

Cara Tabachnick

Cara Tabachnick is a news editor for CBSNews.com. Contact her at [email protected]