Egypt is braced for further dramatic events on Friday as the vanquished Muslim Brotherhood called for a "day of rejection" following a widespread crackdown on its leadership by the country's new interim president, Adly Mansour.

Muslim Brotherhood supreme guide Mohammed Badih appeared on podium at Rabaa El-Adaweya Square sit-in and told a crowd of supporters of Egypt's ousted president Friday that protesters will remain mobilized until Mohammed Mursi's return after he was deposed by the military.

"Millions will remain in the squares until we carry our elected president, Mohammed Mursi, on our shoulders," Badih told the cheering crowd.

"Mursi is the president of all Egyptians," he stressed, calling on the army to "return to the Egyptian people."

"I tell the great army of Egypt that we will protect its back and we ask it to protect us from our enemies. Do not punish the sons of your country, you are more honorable than that," the supreme guide added.

Addressing Grand Imam of al-Azhar Sheikh Ahmed al-Tayyeb, who had backed the army's roadmap that involved Mursi's ouster, Badih said: "You are a symbol but you have no right to speak in the name of Muslims or in the name of Christians."

Badih also addressed Coptic Christian Pope Tawadros II, another key backer of the military's move, calling on him "not to speak in the name of Copts."

A deadly gunfight erupted in Cairo on Friday as thousands of supporters of deposed Egyptian president Mohamed Mursi marched on the Republican Guard headquarters during mass rallies against the Islamist's ouster.

The sound of gunfire was heard as supporters and opponents of Mursi  hurled rocks at each other on the October 6 Bridge leading to Cairo's Tahrir Square, symbol of the 2011 revolt that toppled dictator Hosni Mubarak.

Following the declaration by Mohammed Badih, thousands of Brotherhood supporters marched on the state television building.

Many people were killed and many others wounded as shooting broke out after thousands of Islamist demonstrators approached the headquarters chanting "traitors" and "Mursi is our president".

The Islamists had streamed towards the Guards headquarters on foot from a Muslim Brotherhood rally that attracted tens of thousands at Cairo's Rabaa al-Adawiya mosque.

Shortly before Friday's rallies, around a dozen low-flying military jets screeched across Cairo, a day after warplanes had left a heart-shaped trail of smoke in the sky.

Egypt interim head of state Adli Mansour issued decree dissolving upper house of Parliament and appointed Mohamad al-Tamahi new head of intelligence.

The upcoming hours will prove that all the options are open, until the Egyptians realize the democracy they have always dreamt of.