Bandits have killed scores of residents following a raid on several communities in the Anka and Bukkuyum areas of Zamfara state.
Some villagers said that many motorbike-riding bandits attacked villages, shooting indiscriminately and setting houses on fire.
This appears to be one of the biggest attacks by gunmen on villages in Zamfara in recent months.
Multiple sources have given different casualty figures – some have put the number of the dead at more than 100.
The attacks are said to have started on Tuesday night and continued into Wednesday as the gunmen moved from one village to another.
Police and local officials in Zamfara are yet to respond to enquiries about the attacks.
Local media report that the gunmen appeared to be moving to the western part of Zamfara state to escape an onslaught by Nigerian troops.
A number of vigilantes from some of the affected communities were killed as they tried to repel the attackers.
Hundreds of residents are reported to be fleeing to Anka, one of the big towns in the area.
Communities in Zamfara, and other states in the north-west, have come under persistent attacks in recent years by the gangs, known locally as bandits.
They are sophisticated networks of criminals who operate across large swathes of territory, often stealing animals, kidnapping for ransom and killing those who confront them.
The government has deployed thousands of troops to fight them.
