General Stephen J. Townsend, commander of the US Africa Command (AFRICOM) said "We are seeing the rise of violent extremism in Western Africa, predominantly in the Sahel region."
"We are seeing the arrival of malign actors, and specifically I am thinking of Russian mercenaries from Wagner," Townsend told AFP in Morocco at the conclusion of the four-week long "African Lion" international military exercise.
"This training is not specifically oriented on those problems, but it will help all of our armed forces if we are called to combat this kind of problem in the future," Townsend said.
The Sahel region is a vast territory stretching across the south of Africa's Sahara Desert, incorporating countries such as Burkina Faso, Chad, Mali, Mauritania and Niger.
Islamic State-linked jihadists, whose power was once thought to be waning in the Sahel, have recently expanded their reach and marking their presence with an unprecedented series of civilian massacres.
Mali has been especially hard hit, a former French colony where the strategic landscape has changed dramatically following two coups in August 2020 and May 2021.
Bamako developed closer ties with Moscow, bringing in military personnel that France says are mercenaries from Russia's Wagner group.
African Lion exercises took place close to the border with Western Sahara and Sahrawi refugee camps, where the Algerian-backed Polisario Front independence movement is based.
Townsend said the exercise was "not focused on Algeria at all", but was about "increasing our skill as armies" to work together.
Drawing comparisons with Europe, Townsend said "What we are seeing played out in NATO and Ukraine today shows the value of strong allies and partners working together to defend our common interest."