Britain and the United States yesterday denounced Russia's role in Libya's war and urged Moscow to stop sending mercenaries to support Brigadier General Khalifa Haftar, AFP reported.
"We remain particularly concerned by further reports that external parties continue to provide material, equipment, [and] mercenaries," said Jonathan Allen, the UK's deputy permanent representative to the United Nations.
This comes after a UN report confirmed the presence of Russian and Syrian fighters in Libya.
"Wagner Group activities continue to exacerbate the conflict and prolong the suffering of the Libyan people," Allen said.
"All actors involved in the conflict in Libya must immediately suspend military operations," said American Ambassador Kelly Craft.
Last month, Russia was accused by Libya's interior minister of carrying out a chemical attack in Libya.
Russia's mercenaries used nerve agents against forces loyal to Libya's internationally backed Government of National Accord (GNA) forces in Salah Al-Din area in southern Tripoli, Interior Minister Fathi Bashagha told reporters.
Russia's Wagner Group is one of the most controversial bodies among the mercenaries. It is owned by Yevgeny Prigozhin, a businessman with close links to Russian President Vladimir Putin.
According to Bloomberg, the Wagner Group brought over 1,000 militia fighters to Libya, including Russian pilots who train Haftar's troops and Russian Sukhoi-22 type war planes which have been spotted in Libya's skies.
Mercenaries who previously had field experience in Ukraine are fighting on the front-line in Libya, according to Euronews.
Last January, Turkish President Recep Erdogan said that more than 2,000 Wagner mercenaries were currently fighting in Libya.
Putin has however denied that any Russian servicemen are in Libya acting on behalf of the state or receiving payment from Russia.