More than 40 people were killed when a fire ripped through a Coptic Christian church in a working-class district of Greater Cairo during mass on Sunday, state and religious officials said.The blaze, blamed on an electrical fault, hit the Abu Sifin church in densely populated Imbaba west of the Nile river, part of Giza governorate. Witnesses described panicked scenes as people rushed into the multi-storey house of worship to rescue those trapped but were soon overwhelmed by the heat and deadly smoke.