CAIRO - A large explosion struck outside a Christian church in Egypt's northern city of Alexandria, an Egyptian security source and the Arabic news channel Al Jazeera said on Saturday. The security source in the port city of Alexandria said there had been a blast outside a church at about midnight, but they did not have details on any dead or injured. The television channel cited witnesses who said the blast was caused by a car bomb and that ambulances were in attendance treating an unknown number of casualties. Muslim majority Egypt has a large Christian minority, making up about 10 per cent of the nation's 80 million.