Gunmen have attacked a mosque in central Nigeria's state of Niger, killing nine people, police said Friday while residents gave a higher death toll of 16.

The reason for the attack was not immediately known, but gangs of criminals known locally as bandits have terrorised communities in northwest and central Nigeria for years.

Heavily-armed men on motorcycles stormed the remote Ba'are village in Mashegu district on Wednesday, opening fire on a mosque while worshippers were praying, local police chief Monday Bala Kuryas said.

"The attackers killed nine Muslim worshippers inside the mosque and left some others injured," Kuryas said.

A joint team of police and civil defence paramilitary personnel deployed to the area while the injured were taken to a nearby hospital, the police official said.

Resident Amadu Hamisu said locals collected 16 bodies from the mosque after the attack.

"A total of 16 people who were praying in the mosque were killed. We took their bodies from the mosque," Hamisu told AFP.

Gangs in the area, who are not known to be ideologically driven, have become more violent in recent months.

In October, bandits shot dead 16 Muslim worshippers in a mosque during morning prayers in Maza-Kuka village in the same district.

Analysts and residents have warned that jihadist fighters from the northeast have infiltrated some of the gangs, even taking control over remote villages in Niger state.