Russian soldiers helped to repel an attack on Niger's main airport in the capital Niamey last week which was claimed by the ISIS group, Moscow said on Monday.
Niger's ruling junta earlier said "Russian partners" helped to fend off the rare assault on the capital, which saw 20 attackers killed and four army soldiers wounded, AFP.
"The attack was repelled through the joint efforts of the Russian Ministry of Defense's African Corps and the Nigerien armed forces," the Russian Foreign Ministry said.
"Moscow strongly condemns this latest extremist attack," it added.
ISIS said it staged the attack and released a video of events through its propaganda agency Amaq. The video shows several dozen attackers with assault rifles firing near a hangar and setting ablaze one plane before leaving on motorbikes.
Niger's junta accused Benin, France and Ivory Coast of sponsoring the attack on the airport, which also houses a military base.
Junta chief Abdourahamane Tiani visited the Russian military base to express "personal gratitude for a high level of professionalism", the ministry said.
Russia rarely comments on its military activity in the Sahel region, where Moscow has been increasing its influence in a region that has seen a series of coups.
Facing isolation since its invasion of Ukraine, Russia has tried to build new military and political partnerships in Africa.
Apart from Niger, Russian troops or military instructors have been reported to be deployed in Burkina Faso, Equatorial Guinea, the Central African Republic and Libya.
Russia's African Corps has taken over from the Wagner paramilitary group across the continent.
According to Moscow, the corps helps "fighting terrorists" and "strengthening regional stability" in the Sahel.
Niger's authorities have been fighting the Al-Qaeda-linked Group and the Islamic State in the Sahel (EIS) for the past decade.