Mercenaries working for the Russian private military contractor Wagner PMC (Private Military Company) are operating in Libya, according to UN diplomats.

The Reuters news agency reports that the contractor has clandestinely deployed up to 1,200 people to help Libya's renegade General Khalifa Haftar.

It quotes an experts' report submitted to the UN Security Council's Libya sanctions committee.

The fighters are offering technical support for the repair of military vehicles and also participating in combat operations, the AFP new agency quotes the report as saying.

Gen Haftar's Libyan National Army (LNA) enjoys the backing of Russia, Egypt, Saudi Arabia, the United Arab Emirates (UAE), and Jordan.

He is waging an armed campaign against the UN-recognised government, known as the Government of National Accord (GNA).

Libya has been wracked by conflict since the 2011 uprising, which ousted long-time strongman Muammar Gaddafi.