The Islamic State West Africa Province (ISWAP) militants killed six troops from Nigeria and Niger during an operation this month, a joint military force said on Thursday.
The region where the attacks took place is part of Nigeria’s northeastern Borno state, the centre of the Islamist insurgency in which about 300,000 people have died and millions left dependent on aid, according to the United Nations.
ISWAP, which split from Boko Haram five years ago and pledged allegiance to Islamic State, has been fighting troops from Benin, Cameroon, Chad, Nigeria and Niger in the Lake Chad region.
Spokesman for the Multinational Joint Task Force (MTJF) said two officers and four other ranks from both countries were killed and 16 wounded, without providing an exact date of the attck.
MTJF comprise soldiers from Nigeria and Niger that are targeting Islamist insurgents near Lake Chad basin.