Announcement comes after mass graves were discovered in the city of Tarhuna following retreat by eastern-based forces.
Secretary-General Antonio Guterres has warned the United Nations Security Council (UNSC) that the conflict in Libya has entered a new phase “with foreign interference reaching unprecedented levels”.
Libya was plunged into chaos by the 2011 NATO-backed uprising that toppled and killed its longtime leader, Muammar Gaddafi.
Since 2014, the oil-rich country has been split, with an internationally-recognised government controlling the capital, Tripoli, and the northwest, while renegade military commander Khalifa Haftar in Benghazi controls the east.
Haftar is supported by the United Arab Emirates (UAE), Egypt and Russia, while the government is backed by Turkey.
“The conflict has entered a new phase with foreign interference reaching unprecedented levels, including in the delivery of sophisticated equipment and the number of mercenaries involved in the fighting,” Guterres said on Wednesday.
Russian private military contractor Wagner Group has up to 1,200 people deployed in Libya, strengthening Haftar’s forces, according to a confidential May report by independent sanctions monitors to the UNSC Libya sanctions committee.
The sanctions monitors identified more than two dozen flights between Russia and eastern Libya from August 2018 to August 2019 by civilian aircraft “strongly linked to, or owned by” the Wagner Group or its related companies.
The monitors also listed the details of 122 Wagner mercenaries of “whom many are highly probably operational, or have been operational, within Libya”.
Russia’s UN Ambassador Vassily Nebenzia rejected the accusations of Russian involvement in Libya.
“But we know about other countries’ military personnel, including from those countries that accuse us, to be present on Libyan soil, East and West,” he told the council, calling on all states with influence on the Libyan parties to push for a truce.
United Arab Emirates minister for foreign affairs, Anwar Gargash, told the council there were “roughly 10,000 Syrian mercenaries operating in Libya, approximately twice as many as there were six months ago”.
Guterres denounced the situation during a ministers-level UNSC video conference, expressing particular concern about the military forces massing around the city of Sirte, halfway between Tripoli in the west and Benghazi in the east.
Egypt has warned that any Turkish-backed effort to take Sirte could lead its army to intervene directly.
“We are very concerned about the alarming military build-up around the city, and the high level of direct foreign interference in the conflict in violation of the UN arms embargo, UNSC resolutions, and commitments made by Member States in Berlin,” Guterres said.
Guterres said between April and June this year the UN mission has documented at least 102 civilians deaths and 254 civilians injuries – a 172 percent increase compared with the first quarter of 2020.
He added there were also at least 21 attacks on medical facilities, ambulances and medical personnel.