Prophet has forbidden a war between Muslims. Muslims-who-fight-each-other-will-both-be-in-hell. Even carrying a weapon against another Muslim is Forbidden in Islam. Fighting between Muslims is not Jihad. It is cowardice and an act due to Ignorance.I remind all of you to a saying of our Prophet with warning that both the Killer Muslim and Killed Muslim will both be in hell for fighting each other with weapons.(Ref: Bukhari - Volume 9, Book 88, Number 204)

Abu Bakra Narrates: I heard Allah's Messenger (Sallallahu Alaihi Wasallam) saying, "If two Muslims meet each other with their weapons then the killer and the killed are are both bound for the (Hell) Fire." I said, "O Allah's Messenger (Sallallahu Alaihi Wasallam) It is alright for the killer, but what about the killed one?" Prophet said, “Because the killed one intended to kill just as much as the killer."” [Bukhari & Muslim]