The attackers raided three villages in the Tillabery region, which borders Mali and Burkina Faso. A security source said Islamic State fighters were responsible, while two local sources did not say who was behind it.
Islamic State's local affiliate is active in the zone and has been blamed for previous attacks that killed dozens of civilians and soldiers.
The violence is part of a wider security crisis across West Africa's Sahel region, which is also fuelled by militants linked to al Qaeda and ethnic militias.
Alfouzazi Issintag, mayor of Tillia, the rural commune to which the villages belong, confirmed to Reuters that there had been "a lot of deaths", but did not say how many.
Last Monday, armed men killed at least 58 civilians in Tillabery when they intercepted a convoy returning from a weekly market and attacked a nearby village.
Suspected militants also killed at least 100 civilians on Jan. 2 in raids on two villages in Tillabery, one of the deadliest episodes in the country’s recent history.