(CNN) The US military on Tuesday accused Russia of deploying fighter jets to Libya in support of Russian mercenaries operating there.
"U.S. Africa Command assesses that Moscow recently deployed military fighter aircraft to Libya in order to support Russian state-sponsored private military contractors operating on the ground there," the US military's Africa Command said in a statement. It also said that the aircraft were painted "to camouflage their Russian origin."
Two US defense officials told CNN there "several" Russian military aircraft had been deployed. A third defense official said that "at least" 14 Russian aircraft had been flown to Libya.
Over the weekend, roughly 1,200 mercenaries employed by private Russian contractor Wagner Group pulled back from parts of the country where they had been fighting alongside forces loyal to renegade General Khalifa Haftar, sources told CNN on Tuesday.
Russian contractors have been flying out of the town of Bani Walid over the last 3 days and there have been 6 to 7 flights out per day, Salem al-Nuwairy, the mayor of Bani Walid, told CNN by phone. There are still some Russian fighters in the town, he said.
Russia sent two MiG-29 fighter-bombers from Syria to Libya to protect and secure the retreat of the forces, according to a Western diplomatic source who spoke to CNN.
A source also told CNN that a Russian flying hospital known as "the scalpel" had arrived earlier in Libya to treat wounded Wagner contractors. A detailed look at flight data by CNN shows Russian Air Force IL76 'hospital aircraft' flying into and leaving Benghazi last week.
The US has long accused Moscow of using Russian mercenaries to bolster its preferred side in Libya's civil war, the forces led by Gen. Khalifa Haftar, with the aim of securing access to Libya's vast energy deposits while also establishing a position on NATO's southern flank.
A UN report in early May confirmed the Wagner Group's presence in Libya, including details such as the deployment of snipers and other specialized combat units.
But the Kremlin consistently denies it uses private military contractors in conflicts abroad, and says mercenary groups do not represent the Russian state.
The Russian Ministry of Defense did not respond immediately to a request for comment from CNN.
Earlier this month, the Russian Air Force jets flew from Russia to Khmeimim Air Base in Syria, where the MiG-29 jets were repainted to remove national markings, a US defense official told CNN.
The newly unmarked jets then departed Syria, escorted by Russian fighter aircraft based in Syria, and flew to Libya, landing in Eastern Libya near Tobruk for fuel, according to the official. The warplanes were then delivered to Al Jufra Air Base in Libya, closer to the front lines of the country's civil war.
Since 2011, following the NATO-backed uprising that overthrew the regime of Moammar Gadhafi, Libya has seen factions sparring over control of the oil-rich country.
The conflict intensified in 2014, splitting the country and its political structure between east and west with a contested election and a military operation led by Haftar on behalf of the eastern government hardening the divide.
Haftar's forces have suffered some tactical setbacks in recent days as the UN-recognized government in Tripoli has received backing from Turkey, including armed drones, enabling it to push Haftar's troops farther from the capital.
Haftar had recently reportedly pledged to mount a large-scale air campaign to reverse the recent setbacks.
"The world heard Mr. Haftar declare he was about to unleash a new air campaign. That will be Russian mercenary pilots flying Russian-supplied aircraft to bomb Libyans," Gen. Stephen Townsend, the commander of Africa Command said in the statement Tuesday.
The State Department said Friday that Secretary of State Mike Pompeo spoke with the leader of the Tripoli-based government, Libyan Prime Minister Fayez al-Sarraj " to reiterate U.S. opposition to the continued level of weapons and munitions being brought into the country," according to a State Department spokesperson.