The mosque was evacuated and security forces were chasing armed men who were on top of surrounding buildings.
Egyptian prosecutors are questioning 250 supporters of ousted president Mohamed Morsy on murder and terrorism charges, state media reported on Saturday, as the country’s political crisis continued.
They were arrested on Friday in central Cairo’s Ramses Square and the nearby police station as they attempted to storm it. They also face investigations for allegedly setting buildings on fire in the area.
The probe comes after security forces on Saturday evacuated a mosque in Ramses Square where Mr. Morsy’s backers had taken refuge since Friday after they clashed with police forces and anti-Brotherhood civilians.
Islamist protesters and security forces exchanged fire before the evacuation. Mr. Morsy supporters scaled the mosque’s minaret and fired at security forces surrounding the site, who returned the fire.
The latest cycle of violence began on Wednesday when security forces launched crackdowns on two major pro-Morsy demonstrations in Cairo. About 750 people were killed during the crackdown and the ensuing violence across the country.
The government vowed on Saturday to deal firmly with what it called “powers of terrorism and sabotage.” Live footage from local television stations showed groups of people leaving the al-Fateh mosque under protection of police and military troops.
Some residents tried to attack the evacuees, but were prevented by security troops, a witness said.
Seven of those evacuated were arrested, including a Turk, a Sudanese and two Arabs, a security official told dpa. A senior member in the Muslim Brotherhood, Saad Emara, was also detained.
Ramses Square was one of several areas across Egypt where clashes erupted on Friday between security forces and Morsi supporters, leaving 173 dead, health authorities said on Saturday.
A son of Mohammed Badie, the fugitive chief of Morsy’s Muslim Brotherhood movement, was killed during the fighting, a security source said. Amar Mohammed Badie, a 38-year-old engineer, died of gunshot wounds Friday and his body was taken to a military hospital.
Elsewhere, Hardline cleric Safwat Hegazy, a staunch supporter of Morsi, and six members of the Muslim Brotherhood were also detained in eastern Cairo, a security source told dpa.
However, the interior ministry refused to confirm or deny the arrest.
Hegazy faces charges of inciting murder and violence, the source said.
Earlier Saturday, police arrested the brother of Ayman al-Zawahri, the chief of the al-Qaeda terrorist network. Mohammed al-Zawahri, a jihadist who was released from prison in 2011, was arrested at a security checkpoint in Giza, south of Cairo.
Presidential political adviser Mustafa Hegazy said that Egypt is fighting against “forces of extremism” and the country has vowed to confront it by imposing law and security.
Egypt “faces a war launched by extremist forces that develops everyday to become a kind of terrorism,” Hegazy told reporters.
“We will face extremism and terrorism through enforcing law and sovereignty on everyone. Egypt is not a weak state,” he added.
In a sign of defiance, the Brotherhood has vowed to hold daily protests through next week against the military-backed government, raising fears of further bloodshed.
Interim Prime Minister Hazem Beblawy has proposed legally dissolving the Brotherhood. “The proposal is being studied,” a cabinet spokesman said.
Under emergency rules declared by the government this week, police are allowed to use firearms in self-defence and against demonstrators who attack state buildings.
The army’s overthrow of Morsi July 3, after protests by millions of Egyptians demanding he step down, has deeply divided Egypt, which is the Arab world’s most populous country.
The clampdown on Islamist protesters has drawn international condemnation, mainly from Europe and the United States. However, the Gulf countries have expressed support for Egypt’s interim rulers.
UN Secretary General Ban Ki-moon said in a statement Saturday that he was alarmed by the violent protests and execessive use of force in response.
“He urges those in the street and those in authority to use maximum restraint and shift immediately to de-escalation,” he said in a statement. “He appeals to the authorities and to the political leaders to adopt a credible plan to contain the violence and revive the political process hijacked by violence. Time is of the essence.” In the eastern Libyan city of Benghazi, gunmen threw an explosive device at the Egyptian consulate. The blast damaged the building and cars parked in front of it.