In early December, the acting UN envoy to Libya said about 20,000 foreign and mercenary forces were still in Libya
The UN Security Council on Tuesday called for all mercenaries and foreign fighters to leave Libya, in a unanimous statement that included Russia, which is accused of enabling a Russian contractor to send paramilitaries.
Libya has been wracked by violence and chaos since the toppling and killing of dictator Muammar al-Gaddafi in 2011.
Moscow has been accused of supporting mercenaries fighting against the UN-backed Tripoli Government of National Accord (GNA).
All 15 Security Council members called for the "withdrawal of all foreign fighters and mercenaries from Libya in line with the ceasefire agreement reached by the Libyan parties on 23 October, the commitments of the participants of the Berlin Conference and the relevant United Nations Security Council resolutions."
The statement was released following a closed-door videoconference.
The Security Council also underlined "the importance of a credible and effective Libyan-led Ceasefire Monitoring Mechanism."
At the end of December, UN Secretary-General Antonio Guterres is due to submit options to the Council for the creation of the mechanism, which would operate under the aegis of the United Nations.
The UN has only a small political mission in Libya of around 230 people.
In early December, the acting UN envoy to Libya, American Stephanie Williams, said about 20,000 foreign and mercenary forces were still in Libya.
Two authorities are vying for power in the country: the GNA in Tripoli, recognized by the UN and supported by Turkish military forces, and strongman Khalifa Haftar, supported by the United Arab Emirates, Russia and Egypt.
Wagner, a Russian military contractor, has long been accused of sending fighters to serve the Kremlin's interests in Syria, Libya and countries in sub-Saharan Africa.