As many as 25 suspected gunmen were arrested in connection with the killing of a policeman on duty in Kano State in northwestern Nigeria, local police said Monday.

State Commissioner of Police Ibrahim Idris said the gunmen were nabbed on Sunday after launching attacks in the Kano metropolis.

"The gunmen attacked and killed a policeman at Unguwa Uku area of Kano State on Saturday, while he was on duty," said the police chief, adding that security operatives had been trailing gang for other crimes committed within the state.

Members of the gang had stormed the police officer's duty post on motorcycles early Saturday and opened fire on him, Idris explained.

"The gunmen shot severally in the air after killing the police officer, before fleeing the area," he said further.

According to him, security operatives have continued to comb the area to apprehend other criminals.

Arrest of the 25 assailants in Nigeria's northwestern state of Kano occurred barely 24 hours after authorities of the Nigerian police announced the killing of 14 gunmen in Rivers State located in the oil-rich region of the west African country.

Kano State is among the northern cities often witnessing wave of attacks that have recently plagued the northern and central parts of Nigeria.