Egyptian police fought with angry Muslims outside a Coptic church south of Cairo.
The stone-throwing mob surrounded the church to protest a romance between a Christian man and a Muslim woman.
Police used tear gas on the raging crowd to disperse it.
The woman is said to have converted to Christianity before running away to Turkey with the man. The Muslims accused the church of helping the couple run flee.
The incident has led to attacks on Christian churches and businesses, forcing some shopkeepers to close their doors.