According to a ministry statement, the death toll from Friday's attack could rise because 16 people are still missing and 13 soldiers were injured.
The troops were patrolling in the north of Banibangou department when they "came under a complex ambush by a group of armed terrorists," according to the report, referring to jihadist groups.
The statement also stated that several attackers were killed during the battle, but it did not specify how many.
The attack occurred in Niger's vast western region of Tillaberi, which straddles Burkina Faso and Mali — two countries plagued by jihadist insurgency — and has been targeted numerous times since 2017 by armed groups linked to Al-Qaeda and Islamic State.
The region neighbours the Tahoua area, where heavily armed attackers stormed a camp housing refugees from neighbouring Mali last week.
Nine people were killed in that assault, which a local official said was carried out by “heavily armed terrorists” on motorcycles who fled back into Mali.
Over 61,000 Malian refugees shelter in Tahoua and Tillaberi, according to the United Nations.
After the departure of French soldiers from Mali last year and a scheduled pullout shortly from Burkina Faso, France will field only 3,000 troops in the restive Sahel region — in Niger and Chad — where jihadist groups roam.
All the countries involved are former French colonies