CAIRO (Update1 ) -Hundreds of Egyptians early Friday flocked to Al Tahrir Square in central Cairo for a massive march called to denounce recent sectarian violence. The march will be held as hundreds of angry Copts continued a sit-in outside the State radio and TV building near the Cairo Nile in protest against attacks on churches in the populous district of Imbaba at the weekend. Some 15 Muslims and Copts were killed in sectarian clashes in Imbaba over allegations that a Christian woman converted to Islam was held against her will in a local curch. Over 200 are being detained over the clashes.