Suspected gunmen had on Thursday launched several coordinated bomb attacks on Daura municipal area of Katsina State.
Nigerian forces are trying to regain territory controlled by increasingly well-armed Boko Haram Islamist insurgents in their northeastern stronghold states of Borno, Yobe and Adamawa, which were put under a state of emergency by President Goodluck Jonathan on Wednesday.
Security experts believe a crackdown in the northeast could push insurgent attacks into other regions, or awaken smaller cells that operate in other parts of the north.
“It’s difficult to tell if this is a criminal attack or part of another Islamist cell,” one security source said.
“There have been incidents in the past in Katsina but it certainly hasn’t been an insurgent stronghold.”
Another security source said a bank was raided and prisoners were freed from the police station.
It was not clear who carried out the attack.