Fifty fighters from Nigeria's terrorist group Boko Haram were killed in an overnight clash in the south-east of neighbouring Niger, the government said on Monday.
The Defence Ministry said armed the terrorists, riding in about 20 vehicles, attacked a military post in Toummour, in the restive Diffa region.
The assailants were repelled in a "spontaneous riposte", the ministry said, giving a provisional toll of one soldier wounded and 50 Boko Haram fighters killed.
Reinforcements from the Special Intervention Battalion joined the chase to the shores of Lake Chad, the ministry said.
It said "several suspects" were captured along with two vehicles and weapons.
The region adjoining Nigeria and Chad has repeatedly suffered attacks since 2015 by Boko Haram, which has bases hidden in the vast Lake Chad area, where the borders of Cameroon, Chad, Niger and Nigeria meet.
They had subsided since late last year, but on March 7, Boko Haram fighters, also in about 20 vehicles, raided another army base in Chetima Wango, leaving eight soldiers dead and three missing.
State radio said there were three successive clashes and that vehicles that managed to cross the border into Nigeria were "almost all neutralised" in air strikes by a joint multinational force from Niger, Nigeria, Chad and Cameroon.
The Diffa region is home to 120,000 refugees from Nigeria fleeing the Boko Haram violence, as well as 110,000 people internally displaced within Niger, UN data released in October states.
On Sunday, suspected members of Boko Haram ambushed Nigerian troops in the Banki area of Borno State, also next to the Niger border, killing six soldiers.