Seventeen Niger's soldiers have been killed in an attack by suspected militants near the country's western border with Mali, the defence ministry said.
An army detachment was "the victim of a terrorist ambush near the town of Koutougou,'' the ministry said in a statement.
It added that another 20 soldiers had been wounded, six seriously, with all the casualties evacuated to the capital Niamey. The attack happened on Tuesday.
More than 100 assailants were "neutralised" during their retreat, the army said.
Insurgencies have plagued Africa's Sahel region for more than a decade, breaking out in northern Mali in 2012 before spreading to neighbouring Niger and Burkina Faso in 2015.
The so-called "three borders" area between the three countries is regularly the scene of attacks by rebels affiliated with the Daesh group and al-Qaeda.
The unrest across the region has killed thousands of troops, police officers and civilians and forced millions to flee their homes.
Anger at the bloodshed has fuelled military takeovers in all the three countries since 2020, with Niger the latest to fall to a coup on July 26 when President Mohamed Bazoum was ousted.
Niger is also facing an insurgency in its southeast from militants along its border with Nigeria which is the cradle of a campaign initiated by Boko Haram in 2009.
The coup in Niger has sparked international uncertainty over the potential impact of the crisis on the fight against armed groups in the region as well as economic situations.
