The extraordinary joint Islamic-Arab summit in Riyadh urged the International Criminal Court to investigate "war crimes and crimes against humanity that Israel is committing" in the Palestinian territories, according to a final communique.

Saudi Arabia has sought to press the United States and Israel for an end to hostilities in Gaza, and Crown Prince Muhammad bin Salman, the kingdom's de facto ruler, gathered Arab and Muslim leaders to reinforce that message.

Dozens of leaders including Iranian President Ebrahim Raisi, Turkish President Tayyip Erdogan, Qatar's Emir Sheikh Tamim bin Hamad Al Thani and Syrian President Bashar al-Assad, who was welcomed back into the Arab League this year, attended.

Prince Muhammad affirmed the kingdom's "condemnation and categorical rejection of this barbaric war against our brothers in Palestine". 

"We are facing a humanitarian catastrophe that proves the failure of the Security Council and the international community to put an end to the flagrant Israeli violations of international laws," he said in an address to the summit.

Palestinian President Mahmoud Abbas said Palestinians were facing a "genocidal war" and urged the United States to end Israeli "aggression". 

Raisi hailed the Palestinian Islamist militant group Hamas for fighting against Israel and urged Islamic countries to impose oil and goods sanctions on Israel.

"There is no other way but to resist Israel. We kiss the hands of Hamas for its resistance against Israel," Raisi said in his address. 

The Middle East has been on edge since Hamas fighters rampaged into Israel on Oct. 7, killing 1,200 people.

Since then, Israel has escalated its assault on Gaza, where 11,078 people had been killed as of Friday, 40 percent of them children, according to Palestinian officials.

Fighting intensified overnight into Saturday near Gaza City's overcrowded hospitals, Palestinian officials said.

A baby died in an incubator at Gaza's largest hospital after it lost power, and a patient in intensive care was killed by an Israeli shell, the Palestinian health ministry said.

The war has upended traditional Middle East alliances as Riyadh has engaged more closely with Iran, pushed back against US pressure to condemn Hamas, and put on hold its plans to normalise ties with Israel.

Raisi's trip to Saudi Arabia is the first by an Iranian head of state in more than a decade. Tehran and Riyadh formally ended years of hostility under a Chinese-brokered deal in March. 

Erdogan called for an international peace conference to find a permanent solution to the conflict between Israel and Palestinians.

"What we need in Gaza is not pauses for a couple of hours, rather we need a permanent ceasefire," Erdogan told the summit.

Qatar's emir said his country, where several Hamas leaders are based, was seeking to mediate the release of Israeli hostages and hoped a humanitarian truce would be reached soon. 

"For how long will the international community treat Israel as if it is above international laws?" he asked.

President Joko "Jokowi" Widodo said the “Indonesia Hospital in North Gaza continues to be the target of Israeli attacks and has run out of fuel."

He said a way must be found to make Israel cease fire immediately, before adding: “The OIC must use all fronts to hold Israel accountable for the humanitarian atrocities it has committed."

Saudi Foreign Minister Prince Faisal bin Farhan told reporters there could be no talks about the future of Gaza except "talks about an immediate ceasefire".

The summit also demanded an end to the siege of Gaza, access for humanitarian aid, and a halt to the sale of arms to Israel. 

The kingdom had been scheduled to host two extraordinary summits, of the Organization of Islamic Cooperation and the Arab League, on Saturday and Sunday, but opted for a joint summit because of the "extraordinary" Gaza situation, the Saudi foreign ministry said.

Hamas had urged the summit to take "a historic and decisive decision and move to stop the Zionist aggression immediately". 

Some Arab countries, led by Algeria, called for a complete cut in diplomatic ties with Israel, two delegates told Reuters.

Other Arab countries that have established diplomatic relations with Israel pushed back, stressing the need to keep channels open with Netanyahu's government, they said.

At a press conference in Tel Aviv, Israeli Prime Minister Benjamin Netanyahu urged Arab leadership to "stand up against Hamas."

"It only brought two things to the Gaza Strip - poverty and blood," Netanyahu said. "Hamas is an integral part of the terror axis that Iran leads and that axis of terror and hatred endangers the whole world and the whole Arab world."