The attack happened on Thursday when heavily armed militants attacked an army outpost in Chinagodrar in the country’s west, near the border of Mali, government spokesman Abdourahame Zakari said in a statement Sunday.
Niger’s flag will also be flown at half-staff throughout the territory as the country mourns the troops killed in the raid.
President Mahamadou Issoufou sent his “deepest condolences” to the victims’ families and wished those wounded in the attack a speedy recovery.
More than 50 soldiers died in a militant attack on a military camp in the northeast of Mali in November.
Officials said they have launched an investigation into the incident and urged residents to be resolute in their support as the country continues to wage war against terrorism.
The government said its security forces killed 77 terrorists as they repelled the attackers who came on motorcycles and with several vehicles to the outpost near the Mali border.