The soldiers were killed in an ambush "by Boko Haram terrorists" at around 6 am yesterday as they were patrolling some 20 kilometres (12 miles) from Diffa, the regional capital near Nigerian border, the statement said.
Boko Haram has suffered substantial setbacks in recent months in the face of a counteroffensive by national armies from the region.
At least 17,000 people have been killed since Boko Haram launched an insurgency in 2009 to carve out an Islamic state in northeast Nigeria.
A regional force involving troops from Nigeria, Chad, Cameroon, Niger and Benin is to deploy to fight the Islamists.
