At least 25 people were killed, and several houses were torched after gunmen attacked two villages late on Tuesday in Adamawa State, northeast Nigeria, residents and the state governor said on Wednesday.

The attackers struck Kirchinga in Madagali district and Garaha in neighbouring Hong, two villages on the edge of the Sambisa Forest where Boko Haram and Islamic State West Africa Province (ISWAP) operate.

The twin raids highlight the enduring insecurity in Nigeria's northeast, the epicentre of a 17-year Islamist insurgency, despite years of military campaigns.

Abubakar Lawan Kanuri, the village head of Kirchinga, told Reuters the attackers arrived on Tuesday evening dressed in military uniforms that initially led residents to mistake them for soldiers on patrol. He said 18 bodies were recovered after the gunmen swept through the community.

In Garaha, seven people were killed when gunmen on more than 50 motorcycles stormed the village and attacked a nearby military base, said resident Musa Isa, who added he "narrowly escaped."

They advanced from several directions and hit the military base, killing three soldiers. Four fleeing residents were shot, and a school was also burned. Many villagers have since fled to Mubi, the nearest big town, Isa said.

Adamawa State Governor Ahmadu Umaru Fintiri condemned the attacks as "cowardly acts of terrorism" and vowed not to "let terrorists undermine our efforts to restore peace and stability," according to a statement from his spokesman.