500 soldiers from the forces of Libyan commander Khalifa Haftar will been sent to Russia for treatment.
Reuters has reported that the first 70 have already arrived in Russia.
This is the first obvious cooperation between Moscow and an armed group in Libya, an official and a military source said.
Opponents of Haftar, head of the self-styled Libyan National Army (LNA) based in the east of the country, worry that his engagement with Russia is an attempt to challenge the fragile U.N.-supported government in Tripoli, which he has shunned, Reuters reported.
The fighters will be transfered from Benina airport in Benghazi to Egypt, before arriving in Russia.
Haftar, whose forces have been fighting against an alliance of Islamist militants and former rebels in Benghazi for two years, enjoys close ties to Egypt and the United Arab Emirates. He has cultivated his friendship with Russia, visiting Moscow twice last year to ask for military aid, the Reuters report continued.