Relations between Russia and the U.S. have become more hostile since Moscow invaded Ukraine over a year ago, and Washington and its allies oppose Russian influence in West Africa.
This has worried Western governments and the United Nations who say the move has led to a spike in violence.
Mali, whose government took power in a 2021 military coup, has previously said Russian forces are not mercenaries but trainers helping local troops with equipment from Russia.
The UK, Germany and other nations are pulling troops from a United Nations peacekeeping mission in Mali as security worsens.
Armed groups have a foothold in coastal countries including Benin and Togo and threaten economic leaders Ivory Coast and Ghana.