The number of Russian mercenaries in Mali are expected to increase after France and military allies said they would leave the West African country, US officials said on Thursday. Diplomats fear the exit of 2,400 French troops from Mali — the epicenter of violence in the Sahel region and strongholds of both Al-Qaeda and Daesh affiliates — could worsen violence, destabilize neighbors and spur migration. A French-led mission of 14 mainly European nations with 600-900 soldiers in Mali is also winding up. President Emmanuel Macron said the withdrawal would take four to six months, during which there would be fewer operations against extremists. Two senior US defense officials said, on condition of anonymity, there were between 3,000 and 5,000 private military contractors from the Russian Wagner Group across the African continent. Between 800 and 1,000 contractors from the Wagner group are in Mali, the officials said. “We absolutely expect an increase in Wagner numbers, to go up in Mali as the French leave,” one official said. “What we’re specifically watching for is perhaps any lethal weapons that may move (in).” The European Union has imposed sanctions on the Wagner Group, accusing it of clandestine operations on the Kremlin’s behalf. President Vladimir Putin has said the group does not represent the Russian state, but that private military contractors have the right to work anywhere in the world as long as they do not break Russian law. The officials added that they had not seen a change in Russian mercenary numbers in or out of Mali due to Russia’s military buildup around Ukraine. “But that is something that we’ll always be concerned about and we’ll continue to watc h very closely,” the official added. Russia denies planning an invasion of Ukraine and said this week it was pulling back some of its more than 150,000 troops near the frontier. Washington says Russia is in fact sending more forces.