About 100 people were injured in clashes between demonstrators and security forces. State media said more than 30 security forces were wounded.
The clashes broke out after a demonstrator taking part in a sit-in in front of government buildings in Cairo claimed he was roughed up by government forces, al-Jazeera reports.
The Arab broadcaster adds two members of an advisory council established by the ruling Supreme Council of the Armed Forces resigned in protest of Friday's violence.
Mohamed Morsi, a top-ranking official in the Muslim Brotherhood's Freedom and Justice Party, said SCAF should look into the violence "before it is too late."
Protests in Cairo in early 2011 forced President Hosni Mubarak to step down after nearly three decades in power.
The clashes followed Egypt's second set of parliamentary elections since the revolution. The Muslim Brotherhood's party and the conservative Islamist party al-Nour emerged with the most votes in both elections.
The Arab broadcaster notes violence escalated since early Friday, with security forces storming a protesters' camp near Cairo's Tahrir Square, home of the Egyptian revolution.
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