Libyan military commander Khalifa Haftar was due to arrive in Moscow on Saturday ahead of a meeting with Russia's foreign minister, RIA news agency reported, citing a Russian negotiator.
Haftar is expected to meet Sergei Lavrov on Monday, Lev Dengov, head of the Russian contact group on Libya, told RIA. It was not immediately clear what the pair would be discussing.
At the end of July, Haftar and Libya's Prime Minister Fayez al-Serraj committed during talks in France to a conditional ceasefire and to elections, but a Italian naval mission aimed to help the country curb migrant flows has fuelled tension this month.
Haftar's self-styled Libyan National Army controls much of eastern and southern Libya.
It has rejected a UN-backed government in Tripoli that is struggling to assert authority over an array of armed factions which have been competing for control since the 2011 fall of Muammar Gaddafi.
Haftar has held talks with Russian officials before and in January he was given a tour of a Russian aircraft carrier in the Mediterranean.
The head of the UN-backed government visited Moscow in March, and the Kremlin said then it wanted to help repair the damage it said had been done by Western involvement in the country.