A bomb has ripped through a regional police headquarters in the largest city in Nigeria's Muslim North, tearing away its roof and blowing out windows in a blast felt miles away.
Meanwhile, other explosions could be heard across Kano, Nigeria's second-largest city. Police could not be immediately reached for comment.
The blast at the police building occurred just after 5pm. Police kept reporters away from the building.
A spokesman for the Nigeria Immigration Service in the capital Abuja said officials in Kano told him the blast shook their nearby office and came from a bomb.
An AP reporter could see a plume of smoke also rising from another neighbourhood in the city as people began fleeing the area.
Another reporter said the explosion was powerful enough to shake his car several miles away.