A suicide blast in the northern Nigerian city of Kano has killed four people, police say.

They say that the blast happened in a street with many bars and night spots. Witnesses say that the explosion was caused by a bomb in a car in the predominantly Christian area of Sabon Gari. The blast could be heard from several miles away. The militant Islamist group Boko Haram has carried out attacks in Kano state and other areas of northern Nigeria.