Security forces cleared a mosque in central Cairo late Saturday in which supporters of the Muslim Brotherhood had been baracaded since Friday. Some 400 arrests were made, including a handful of foreigners.

Al-Fath Mosque on Ramsis Square in the heart of the capital had been cordoned off, with soldiers outside and gunmen inside trading fire Saturday.

Some 1,500 Brotherhood supporters took refuge in the mosque Friday amid intense clashes on Ramsis Square between supporters of deposed president Mohamed Morsi and local residents and security forces. Some 173 were killed in Friday's clashes, according to health ministry figures.

Earlier Saturday, following a long stand-off, police made a path for most Brotherhood supporters trapped inside to exit the mosque safely. The Brotherhood claimed gunmen had been stationed inside the mosque by the police, asserting it remains committed to non-violence.

A presidential advisor, meanwhile, said Egypt was waging a war against terrorism and extremists as the country plunges deeper into turmoil following the ouster of Morsi which pitted Islamists against the new army-backed government.

"We are facing a war launched by extremist forces developing daily into terrorism," Mostafa Hegazy told reporters Saturday.

Stakes rise

As tensions run high, Egypt's interim premier, Hazem El-Beblawi, has proposed banning Morsi's Muslim Brotherhood, fueling fears of a deadly showdown between state authorities and the once-ruling group that operated in shadows for decades until the downfall of long-time strongman Hosni Mubarak in 2011.

Government spokesman Sherif Shawky said the idea of a ban was currently being mulled by authorities.

The interior ministry said that some 1,004 Muslim Brotherhood "rioting elements" had been arrested against the backdrop of Friday violence that drove the death toll to around 800 since Wednesday.

The latest wave of violence came after the Brotherhood called a "Day of Rage" to denounce the bloody dispersal of pro-Morsi protest camps Wednesday that claimed more than 600 lives, including 43 policemen.

Tens of churches were set on fire and police stations came under attack, allegedly by Morsi loyalists, across Egypt. The Egyptian Churches Council, led by Coptic Orthodox Pope Tawadros II, voiced alarm in a statement Saturday over recurrent anti-Coptic violence, condemning what it termed "international interference and misleading" against Egyptians "and their right to fight terrorism."

The health ministry said Friday violence killed at least 173 people across Egypt, including 95 in Cairo and 25 in Alexandria. Among those killed Friday was the son of Mohamed Badie, the supreme guide of the Muslim Brotherhood.

The Brotherhood called for a week of daily demos starting Saturday, dubbed "The Departure Week," to denounce the police crackdown on its supporters. There was no sign of mass rallies Saturday.

International reactions

Violence has thrown Egypt deeper into polarisation and has drawn a chorus of international condemnation. Both German and Qatari foreign ministers voiced alarm over recurrent clashes and the numbers of victims.

The European Union said its 28 members will hold a high-level meeting Monday to review the crisis in Egypt, with EU foreign policy chief Catherine Ashton describing the death toll as "shocking."

Britain and France also urged an "end of violence and repression, respect for the human rights of all, and the resumption of inter-Egyptian dialogue."

Saudi Arabia's King Abdullah, who gave his blessing to the military ouster of Morsi, said his country would support Egypt in its battle against "terrorism."