A gunfight between police and unknown attackers in Nigeria\'s restive north on Wednesday left one officer and a civilian dead, police said. Gunmen launched the early morning attack on a building near a police post in the northwestern city of Sokoto, which has not been targeted by Boko Haram Islamists, although the group has threatened to strike there. \"There was a dawn attack on a building opposite a police station. Policemen engaged the attackers in a shootout,\" Sokoto police spokesman Mustapha Sani said. \"A police inspector coming out of a nearby mosque and a tailor were hit and killed by stray bullets.\" Boko Haram has repeatedly attacked police in northern Nigeria, but Sani said the targeted building in Sokoto\'s Yan Marina district was residential. \"We are still trying to establish who the attackers were. They could be assassins, Boko Haram members or robbers,\" the spokesman further said. Nigeria\'s police have raided suspected Boko Haram hideouts in Sokoto and have claimed the arrests of alleged group members in the city. A Briton and an Italian were killed in March by their captors in Sokoto following a botched rescue operation authorised by London. Nigerian President Goodluck Jonathan blamed the kidnappings on Boko Haram but the group has denied involvement. The radical sect has claimed attacks that have killed more than 1,000 people in Nigeria since mid-2009.