Clashes in Nigeria\'s restive northeast killed five Boko Haram Islamists and 13 fighters from a vigilante group which has fought several battles with the insurgents in recent weeks, a state government official said. \"The youths (vigilantes) in Benishiek (in Borno state) lost 13 of their members. Twelve died when they were ambushed around 12:30 am and another one died in the hospital,\" said Garba Ngamdu, an aide to the state governor, in an account corroborated by members of the vigilante force