"Yesterday around 1:30 p.m. (1230 GMT), a detachment of the Nigerian Armed Forces, in motion between Boni and Torodi, encountered a terrorist ambush near the locality of Koutougou (52 km southwest of Torodi)," the ministry stated.
It added that the prompt soldier response and air-ground engagement at the encounter scene facilitated enemy handling.
The wounded evacuated to Niamey, the ministry said.
The area known as the "three borders" (of Niger-Mali-Burkina Faso), where Torodi is located, has become a place in recent years where terrorist groups carry out deadly attacks on the borders, targeting both military and civilian populations.