Three soldiers and 14 attackers died in an assault earlier this week on an army camp in western Niger near the border with Mali, the defence minister said.
Heavily armed "terrorists" in a dozen 4x4 vehicles led the attack early Monday morning on the military post in the West African country's Tahoua region, he said.
"After two hours of intense fighting, the vigorous response of our defence and security forces enabled us to repel the attack and push back the assailants," the minister said Tuesday in a statement read on state TV.
"A vehicle packed with explosives was seized" by the army along with weapons and ammunition, he said.
Militants operate on Niger's northern borders with Mali and Libya, while its southeastern border with Nigeria is plagued by the Boko Haram group.
The statement added that the attackers had fled towards Mali after the battle at the Agando camp, which also left four soldiers and several attackers wounded.
It came as armed men launched an attack Tuesday evening on another army post, also in Niger's west, according to a security source who could not give an immediate death toll.
Tuesday's attack took place in the Inates area, the source said, adding that the situation was "under control" and reinforcements had been sent.
"The attackers came in their dozens, in small groups on motorcycles," and surrounded the camp, she said.
In July, a faction of Boko Haram backed by the Islamic State group claimed responsibility for an attack on an army camp in Inates that killed 18 soldiers.
Niger is part of a five-nation anti-jihadist task force known as the G5, set up in 2014 with Burkina Faso, Mali, Mauritania and Chad.
Thousands of civilians and soldiers have died in violence across the vast region with porous borders, known as the Sahel, which began when armed Islamists revolted in northern Mali in 2012.