By Nidal al-Mughrabi

GAZA About 500 Palestinians were killed in a blast at a Gaza City hospital on Tuesday that Israeli and Palestinian officials blamed on each other and that ignited protests in the West Bank and around the Middle East.

Health authorities in the Hamas-ruled Gaza Strip said that an Israeli air strike caused the blast while Israel's military attributed it to a failed rocket launch by the Palestinian Islamic Jihad militant group.

The blast was the bloodiest single incident in Gaza since Israel launched a bombing campaign to retaliate for an Oct. 7 Hamas assault on southern Israeli communities that killed 1,300 people. The strip is 45 km-long (25-mile) enclave and home to 2.3 million people.

The blast took place on the eve of a visit by U.S. President Joe Biden to Israel to show support for the country in its war with Hamas, the Islamist group that rules the Gaza Strip, and to hear how Israel plans to minimize civilian casualties.

Reuters could not independently verify who was responsible for the blast.

Before Tuesday's blast, health authorities in Gaza said at least 3,000 people had died in Israel's 11-day bombardment that began after Hamas' Oct. 7 rampage in which an estimated 200 people were taken back into the Gaza Strip as hostages.

Regardless of who is found responsible for the explosion, which Hamas said had killed patients and others left homeless by Israeli bombardment, it will complicate efforts to contain the crisis.

In one sign of this, Jordan's foreign minister, Ayman Safadi, cancelled a summit his country was to host in Amman with Biden and the Egyptian and Palestinian leaders.

In another, Palestinian security forces fired tear gas and stun grenades to disperse protesters in the occupied West Bank city of Ramallah who were throwing rocks and chanting against Abbas as popular anger boiled.

The blast drew condemnation across the Arab world, and protests were staged at Israel's embassies in Turkey and Jordan and near the U.S. embassy in Lebanon, where security forces fired tear gas toward demonstrators.

Television footage showed protests in Yemen's southwestern city of Taz, as well as in the Moroccan capital Rabat and Iraq's capital, Baghdad.

Lebanon's Iran-backed Hezbollah militant group denounced what it said was Israel's deadly attack on the Al-Ahli al-Arabi hospital in Gaza, which is run by the Anglican church, and called for "a day of unprecedented anger" against Israel and Biden's visit.

CLAIMS AND COUNTER CLAIMS

There were competing claims and denials from Israeli and Palestinian officials over who was responsible.

The health minister in the Hamas-run government of Gaza, Mai Alkaila, accused Israel of a massacre. A Gaza civil defence chief said 300 people were killed and a health ministry official said 500 were killed.

Israeli Prime Minister Benjamin Netanyahu minced no words in blaming Palestinian militants for the explosion.

"The entire world should know: It was barbaric terrorists in Gaza that attacked the hospital in Gaza, and not the IDF," he said, referring to the Israel Defense Forces. "Those who brutally murdered our children also murder their own children."

The IDF blamed a Palestinian militant group called Palestine Islamic Jihad which, like Hamas, is viewed by the United States as a foreign terrorist organization.

"Following an additional review and cross-examination of the operational and intelligence systems, it is clear that the IDF did not strike the hospital in Gaza," IDF Spokesperson Rear Admiral Daniel Hagari said in a video statement.

"The hospital was hit as a result of a failed rocket launched by the Islamic Jihad terrorist organization," he said.

Daoud Shehab, a spokesman for Islamic Jihad, told Reuters: "This is a lie and fabrication, it is completely incorrect. The occupation is trying to cover for the horrifying crime and massacre they committed against civilians."

During the last Israeli-Hamas conflict in 2021, Israel said Hamas, Islamic Jihad and other militant groups fired around 4,360 rockets from Gaza of which around 680 fell short of Israel and into the Gaza Strip.

Clashes with Palestinian security forces broke out in a number of other cities in the West Bank, which is ruled by Abbas' Palestinian Authority, late on Tuesday, witnesses said.

After Hamas officials initially blamed Tuesday's hospital blast on an Israeli air strike, Arab countries, Iran and Turkey swiftly condemned it. The Palestinian prime minister called it "a horrific crime, genocide" and said countries backing Israel also bore responsibility.

(This story has been corrected to say that Mai Alkaila is the Palestinian Authority's health minister, not health minister of Gaza's Hamas-run government, in paragraph 14)

(Reporting by Nidal al-Mughrabi, Bassam Massoud and Nuha Sharaf in Gaza, Ari Rabinovitch, Dan Williams, Henriette Chacar, Dedi Hayun, Maayan Lubell, Emily Rose, James Mackenzie and John Davison in Jerusalem, Humeyra Pamuk in Tel Aviv, Parisa Hafezi in Dubai, Hatem Maher, Ahmed Tolba and Omar Abdel-Razek in Cairo, Trevor Hunnicutt, Nandita Bose, Rami Ayyub and Katharine Jackson in Washington, Michelle Nichols at the United Nations, Writing by Peter Graff, Angus Macswan and Arshad Mohammed; Editing by Mark; Heinrich and Howard Goller)