The attackers, described as "mercenaries" by the Ministry, used eight vehicles and more than 200 motorbikes in the raid on the base in Bani-bangou on Thursday, according to the statement read out on state television.
Islamic State claimed responsibility for the attack on the army base in a statement on its Telegram channel on Friday.
Niger, like other countries in West Africa's Sahel region, is battling Islamist militants linked to al Qaeda and Islamic State.
Troops carried out aerial and ground search operations to secure the area after the attack, the Ministry said without going into more detail on the assault.
--Reuters--