Turkish President Recep Tayyip Erdogan on Friday urged the Islamic world to show greater unity in supporting the Palestinians, saying Muslim leaders needed to overcome divisions to combat Israel's "brutality".
Mr Erdogan first addressed thousands in Istanbul at a rally he personally called and barely an hour later chaired an emergency summit of Islamic heads of state he had summoned at a few days' notice.
The Turkish strongman has been outspoken over the killing by Israeli forces on Monday of some 60 Palestinians on the Gaza border as well as the move of the US embassy to Israel from Tel Aviv to Jerusalem.
"The time has come to stand against Israel's tyranny," Mr Erdogan told a sea of protesters waving Turkish and Palestinian flags.
"I invite all Muslims and all humanity to take action... against those who drag our region and the world into catastrophe with their religious fanaticism," he added.
In a hard-hitting speech before Mr Erdogan's address, Prime Minister Binali Yildirim said Israel was "imitating Hitler and Mussolini" by occupying Palestinian territory and disregarding international law.
Speaking at the opening of the summit, Mr Erdogan compared Israel's actions against the Palestinians in Gaza to the Nazi persecution of the Jews in the Holocaust during World War II.
"There is no difference between the atrocity faced by the Jewish people in Europe 75 years ago and the brutality that our Gaza brothers are subjected to," he said, accusing Israel of using methods "similar to the Nazis".
Around six million Jews were killed by the Nazis during World War II in the Holocaust.
Mr Erdogan is hoping the extraordinary meeting of the Organisation of Islamic Cooperation (OIC) will be able to bridge divisions in the Islamic world to take a strong stance against Israel.
He told the rally that Muslims had too often given a "shy and cowardly" image to their foes and failed to sort out internal disagreements.
Describing the issue of Jerusalem as a "test", he said: "If we need to speak clearly, the Islamic world failed in the Jerusalem test."
This is the second emergency OIC meeting Mr Erdogan has hosted in the space of half a year after the December 2017 summit, also in Istanbul, that denounced US President Donald Trump's decision to recognise Jerusalem as the capital of Israel.
A draft summit communique called for "international protection for the Palestinian people" and condemns Israel's "criminal" actions against "unarmed civilians".
The text also accused the US administration of "encouraging the crimes of Israel".
However, as in 2017, disputes between the OIC's key players -- notably between Sunni kingpin Saudi Arabia and Shiite Iran -- may prevent the adoption of any measures going beyond harsh rhetoric.
Riyadh - which appears to have softened its stance on Israel as the influence of powerful Crown Prince Mohammed bin Salman has grown - and its allies fear alienating the United States with tough measures against Tel Aviv.
Saudi Arabia's chief foreign policy preoccupation, shared with Israel, is ensuring US backing to contain Iran which both Riyadh and the Jewish state see as the main threat to regional peace.
Iranian President Hassan Rouhani is a key participant and overcoming the enmity between Tehran and Riyadh will be crucial for the Turkish hosts.
Jordanian King Abdullah II is present although the Palestinians are represented by prime minister Rami Hamdallah and not president Mahmud Abbas who this week had surgery on his ear.
Egyptian Foreign Minister Sameh Shoukry and Saudi counterpart Adel Al Jubeir have come but not their heads of state.
Mr Erdogan has long craved a role as a Muslim leader within the entire Islamic world, rarely holding back with tirades against Israel even though Ankara has diplomatic relations with the Jewish state.
Tensions with Israel and hosting such a meeting also does Mr Erdogan no harm with his core supporters as Turkey heads to presidential and parliamentary polls on June 24.
In a diplomatic crisis threatening a 2016 deal that allowed the resumption of full ties, Turkey has ordered the Israeli ambassador to leave for an unspecified period of time over the killings.
"I will say openly and clearly that what Israel is doing is banditry, brutality and state terror," Mr Erdogan told the summit.