Egyptian security officials say clashes between Muslim and Christian protesters have injured more than 50 people in Cairo.
The violence erupted when a mob attacked a group of Coptic Christians staging a sit-in outside the state television building in central Cairo. The Saturday brawl continued into early Sunday.
Witnesses say people threw rocks and set vehicles on fire. Police and army troops fired shots in the air to disperse the crowd.
The latest sectarian violence comes about a week after Muslim mobs attacked Egypt's Coptic Christian minority, burning two churches and leaving 15 people dead in Cairo's slum of Imbaba.
Christians make up about a tenth of Egypt's 80-million people. They joined forces with Muslims during the protests that ousted long-time president Hosni Mubarak earlier this year, but sectarian strife has since intensified.