A Gaza hospital strike that killed at least 500 people has unleashed a torrent of condemnation across the Arab world, with even allies blaming Israel for the attack, despite its denials.

The denunciations coincided with angry rallies in Lebanon, Jordan, Libya, Yemen, Tunisia, Turkey, Morocco, Iran and the Israeli-occupied West Bank, with more planned on Wednesday following calls for a "day of rage" across the region.

U.S. President Joe Biden vowed to show the world that the U.S. stands in solidarity with Israelis during his visit there Wednesday, and offered an assessment that the deadly explosion at a Gaza Strip hospital apparently was not carried out by the Israeli military.

"Based on what I've seen, it appears as though it was done by the other team, not you," Biden told Israeli Prime Minister Benjamin Netanyahu during a meeting. But Biden said there were "a lot of people out there" who weren't sure what caused the blast.

U.S. President Joe Biden landed in Tel Aviv on Wednesday as Middle East anger flared after hundreds were killed when a rocket struck a hospital in war-torn Gaza.

Biden has expressed "iron-clad" support for Israel in its war against Hamas over the October 7 attacks and was welcomed on the tarmac by Prime Minister Benjamin Netanyahu.

A strike on a Gaza hospital compound which health officials there said killed at least 500 people has provoked outrage and condemnation from around the world, with protests on the streets of Amman, Tunis, Beirut and Tehran.

Hamas called Tuesday’s hospital blast “a horrific massacre,” saying it was caused by an Israeli strike.

The Gaza Health Ministry said an Israeli airstrike Tuesday hit a Gaza City hospital packed with wounded and other Palestinians seeking shelter, killing hundreds. If confirmed, the attack would be by far the deadliest Israeli airstrike in five wars fought since 2008.

Photos from al-Ahli Hospital showed fire engulfing the hospital halls, shattered glass and body parts scattered across the area. The ministry said at least 500 people had been killed.

For hours and hours, Moen Abu Aish digs through the rubble of demolished homes to find survivors of Israeli airstrikes, toiling in a vast and desperate search complicated by the shortage of critical supplies and the sheer scope of destruction across the Gaza Strip.

Even as rescue worker Abu Aish, 58, and his colleagues struggle to pry lifeless bodies from the concrete and twisted metal where residential towers once stood, the death toll keeps rising. Gaza's Health Ministry has reported that Israel's bombardment — launched after Hamas mounted an unprecedented attack on Israel on Oct. 7 — has killed more than 2,700 Palestinians, many of them women and children.

Israel on Tuesday bombed areas of southern Gaza where it had told Palestinians to flee to ahead of an expected invasion, killing dozens of people. Meanwhile, mediators struggled to break a deadlock over delivering aid to millions of increasingly desperate civilians in the territory, which has been besieged and under assault by Israel since a brutal attack by Hamas militants.

Flaring violence along Israel's border with Lebanon also led to concerns over a widening regional conflict that diplomats were working to prevent.

Turkey's top diplomat said Tuesday that his country had been in touch with Hamas over some 200 Israeli and foreign hostages it is holding in Gaza, following requests from several governments.

"So far, we have received requests from various countries for the release of their citizens. As a result, we started to discuss these issues, especially with the political wing of Hamas," Foreign Minister Hakan Fidan told a news conference in Beirut, alongside his Lebanese counterpart, Abdallah Bou Habib.

Intense talks are on to free hostages held by Hamas after its attack on Israel, French President Emmanuel Macron said Tuesday, after the mother of a French-Israeli captive begged world leaders to intervene.

"I want to be very cautious here... so as not to endanger the intense talks we are currently conducting," Macron told reporters in the Albanian capital Tirana. "But they are progressing and we are following these talks hour by hour."

Iran's supreme leader Ayatollah Ali Khamenei warned Tuesday that "no one can stop" forces opposed to Israel if it keeps up its bombardment of Gaza in response to the surprise attack by Hamas.

The Islamic republic has maintained close contacts with its allies across the region since Hamas militants stormed across the Gaza border with Israel and killed more than 1,400 people, most of them civilians.