The United States on Thursday called for the immediate withdrawal of Russian and Turkish forces from Libya, after a deadline for them to leave was ignored.
This appeal marked a firmer expression of US policy toward oil-rich Libya under the new administration of President Joe Biden.
"We call on all external parties to respect Libyan sovereignty and immediately cease all military intervention in Libya," the acting US ambassador Richard Mills said during a UN Security Council meeting on Libya.
Under a UN-backed ceasefire signed October 23, foreign troops and mercenaries were to pull out of Libya within three months. That deadline passed on Saturday with no movement announced or observed on the ground, AFP reported.
"Per the October ceasefire agreement we call on Turkey and Russia to immediately initiate the withdrawal of their forces from the country and the removal of the foreign mercenaries and military proxies that they have recruited, financed, deployed and supported in Libya," said Mills.
The UN estimates there are some 20,000 foreign troops and mercenaries in Libya helping the warring factions: the Government of National Accord in Tripoli and the Libyan National Army (LNA) in the east.
Mercenaries in Libya include several thousand each from Syria and Sudan and a thousand from Chad, a diplomat said on condition of anonymity.
In this context, Russia denies having any military personnel in Libya.
"We don't have any military personnel or servicemen on Libyan soil. Therefore there is no Russian military intervention in Libya," a spokesperson for the country's mission told AFP.
"If there are any Russian nationals as mercenaries, which we cannot totally exclude, those who hired them should be addressed to withdraw them."
At Thursday's council meeting, most members also called for the withdrawal of foreign forces from Libya and respect for an arms embargo in force since 2011.
Russian ambassador Vassily Nebenzia in his remarks to the council made no mention of the presence of foreign fighters.
UN Secretary-General Antonio Guterres also called for the departure of the fighters.
In a declaration adopted unanimously Thursday by the 15 Security Council members -- including Russia -- the panel "called for the withdrawal of all foreign fighters and mercenaries from Libya without further delay."
The UN said the arms embargo is being violated as cargo planes arrive with weapons for the two warring sides.
"This blatant foreign interference continues," said acting UN envoy Stephanie Williams, while noting that a ceasefire was still in place.
UN-sponsored talks among the two sides in Libya are expected to resume in the near future in Geneva. Libya is scheduled to hold elections in December.