Russian fighters in Libya were flown out of a town south of Tripoli by their Libyan allies after retreating from frontlines at the capital, Reuters reported the town's mayor as saying.
The reported departure of the Russians is another blow to the Libya National Army (LNA) of eastern Libyan military leader Khalifa Haftar, and his foreign allies.
Haftar's forces, backed by Russia, Egypt and the United Arab Emirates, have been trying to capture the capital for 13 months, but suffered a string of defeats in recent weeks in fighting against Turkey-backed forces of the Tripoli government.
In the past two days, LNA forces have withdrawn from some positions in southern Tripoli in what they described as a humanitarian gesture. Forces allied to the internationally recognised government re-entered some of those areas.
Libya has been without central government control for nine years, and since 2014 it has been divided between two main rival governments in the east and the west. The conflict has turned into a proxy war between the foreign allies of the two sides.
The Russian fighters allied to the LNA retreated with their heavy equipment from the capital to the airport of Bani Walid, a town some 150 km (93 miles) southeast of Tripoli, said Salem Alaywan, Bani Walid's mayor.
He told Reuters the Russians had now been flown out of western Libya to Jufra, a remote central district and LNA stronghold.
"They (the Russians) were flown in three military planes to Jufra and their military vehicles were driven there," he said.
LNA spokesman Ahmed Mismari denied any foreigners were fighting with his force. But the Russians' presence has been widely documented by diplomats and journalists. Pictures purportedly showing Russians, some sitting on trucks, in Bani Walid were posted on social media.
The Tripoli government, known as the GNA, has with Turkish help made sudden strides, seizing a string of towns from the LNA, capturing the strategically important Watiya airbase and destroying several Russian-made air defence systems.
"The withdrawal (of the Russians) from the greater Tripoli area is a very meaningful event because it deprives the LNA of its most effective, best-equipped foreign fighting forces on that key front," said Jalel Harchaoui, research fellow at the Clingendael Institute said.
The GNA has deployed Syrian fighters allied to Turkey, while Haftar is also using Sudanese. The LNA still holds the town of Tarhouna south of Tripoli with the help of a local armed group.