Egypt was on edge Monday after a night of sporadic violence outside Cairo's Coptic cathedral which had come under attack by police and armed civilians following funeral prayers for four Christians. Calm was restored to the central neighbourhood of Abbassiya where police deployed in force outside St Mark's cathedral, and where several Copts were still gathered on Monday morning. One person was killed and more than 80 injured in Sunday's violence, which erupted after mourners were pelted with stones as they left the cathedral, a security official told AFP. Interior Minister Mohammed Ibrahim inspected the scene of the clashes overnight, an official said. On Sunday, live television footage showed police firing tear gas at the cathedral, symbol of the Coptic community which has long complained of discrimination and marginalisation. The bloodshed underscores simmering hostility that has regularly seen violence between President Mohamed Mursi's main Islamist allies and a broad opposition. It also highlights sectarian tensions brewing for years. Christians form between six and 10 percent of Egypt's population of nearly 83 million people.