CAIRO — Egyptian President Mohamed Morsi said he had cut all diplomatic ties with Damascus on Saturday and called for a no-fly zone over Syria, pitching the most populous Arab state firmly against President Bashar Al Assad.

Addressing a rally called by Sunni Muslim clerics in Cairo, the Sunni Islamist head of state said: “We decided today to entirely break off relations with Syria and with the current Syrian regime.”

He also warned Assad’s allies in the Iranian-backed Lebanese Shiite group Hizbollah to pull back from fighting in Syria.

“We stand against Hizbollah in its aggression against the Syrian people,” Morsi said. “Hizbollah must leave Syria — these are serious words. There is no space or place for Hizbollah in Syria.”

Morsi, who faces growing discontent at home over the economy and over fears that he will pursue an Islamist social agenda, said he was organising an urgent summit of Arab and other Islamic states to discuss the situation in Syria, where the United States has in recent days decided to take steps to arm the rebels.

Mursi, who spoke at a packed 20,000-capacity stadium and waved Syrian and Egyptian flags after his entrance, also urged world powers not to hesitate to enforce a no-fly zone over Syria. The crowd of his supporters chanted: “From the free revolutionaries of Egypt: We will stamp on you, Bashar!”

Morsi said Syria was the target of “a campaign of extermination and planned ethnic cleansing fed by regional and international states”, partly in reference to Iran, though he did not name the Shiite Islamic republic.

Morsi said: “The Egyptian people supports the struggle of the Syrian people, materially and morally, and Egypt, its nation, leadership... and army, will not abandon the Syrian people until it achieves its rights and dignity.”