25 Nigerien soldiers were killed and six others were injured following an attack by a suspected Islamist militia on Thursday, the Nigerien government said in a statement.
63 suspected militants were also killed in the attack which happened at an army outpost in west Niger close to the border with Mali.
The statement did not identify which group the militants belonged to.
On Wednesday, a top UN official in West Africa and the Sahel warned of a devastating surge in terrorist attacks against civilian and military targets in the region.
Mohamed Ibn Chambas said that the humanitarian consequences are alarming and the attacks had shaken public confidence.
Chambas also noted that the geographic focus of terrorist attacks had shifted towards the east from Mali to Burkina Faso and was increasingly threatening West African coastal states.
Islamist groups linked to Al-Qaeda and Islamic State have stepped up their attacks against the Nigerien military in the past year.
In December 2018, Islamist militants killed 71 soldiers in an attack on a military camp in Niger near the border with Mali, in what is considered one of the deadliest attacks against the Nigerien military ever.
In October, twelve soldiers were killed and eight others wounded in an overnight attack by suspected Boko Haram gunmen in southeastern Niger.
In July, at least 18 soldiers were killed and four others were reported missing following a suspected Islamist attack on a military camp in western Niger.
