Soldiers encountered hundreds of fighters near the village of Funio on Saturday and came under heavy fire. Dozens of he militants were killed in the fight, the government said.
The attack is part of a wider wave of violence by groups linked to al Qaeda and Islamic State that since 2017 has swept across West Africa's Sahel region, a band of arid terrain south of the Sahara Desert.
Some of the worst attacks have been centred in the border region of Niger, Mali and Burkina Faso. Thousands of civilians have been killed in the region, and millions displaced.