CNN  — 

Construction on an enormous trench across Libya, dug by Russian-backed mercenaries Wagner, is raising fears that foreign fighters will not withdraw from the country by Saturday, as a UN-brokered peace deal insists.

US officials are also concerned over the long-term goals of the Kremlin ally in the war-torn state. One intelligence official notes that the trench is a sign that Wagner, which, the official said, has its largest global presence in Libya, is “settling in for the long haul.”

The trench, which extends dozens of kilometers south from the populated coastal areas around Sirte towards the Wagner-controlled stronghold of al-Jufra, can be seen on satellite imagery and is bolstered by a series of elaborate fortifications.

CNN has contacted the Russian government for comment and received no response.

A simmering conflict has split Libya for months, with the internationally-recognized Government of National Accord (GNA) in the capital Tripoli, backed by Turkey, in an enduring stalemate against the Libya National Army (LNA) in the East, led by General Khalifa Haftar and backed by Russia and the United Arab Emirates.

This recent conflict has claimed more than 2,000 lives, according to UN data, and shattered an oil-rich, strategically vital Mediterranean state. An October peace deal, brokered by the United Nations, was meant to see all foreign forces leave the country by January 23, one of a number of confidence-building measures.

The trench and fortifications appear designed to impede or stop a land attack on LNA controlled areas in the east, running through the populated coastal areas of Libya that have seen the most clashes since the 2011 fall of the regime of Moammar Gadhafi.

The GNA have posted images of excavators and trucks creating the ditch and berm that runs alongside it and said that work appeared ongoing as recently as this month.

The trench, the US intelligence official said, is another reason “we see no intent or movement by either Turkish or Russian forces to abide by the UN-brokered agreement. This has the potential to derail an already fragile peace process and ceasefire. It will be a really difficult year ahead.”

Open-source monitoring says it has mapped a series of more than 30 defensive positions dug into the desert and hillsides that stretch for about 70 kilometres.

Satellite imagery from Maxar, seems to show both the trench stretching along a main road, and the fortifications dug, also by Wagner mercenaries and their contractors.

Images show a build-up of defenses around the Jufra airbase, and also the Brak airfield further south, where apparent radar defenses have been installed and fortified.

Salaheddin Al-Namroush GNA Defense Minister, said to CNN: “I don’t think anyone digging a trench today and making these reinforcements is leaving anytime soon.”

Claudia Gazzini, from the International Crisis Group, told CNN the trench was “indeed worrying,” and that talk of it “has been circulating between diplomats for the past few weeks. It is ongoing and would suggest Moscow is keen to cement its presence in Libya.”

Analysts have said the Kremlin is keen to boost its military presence and influence in the Mediterranean, along NATO’s southern underbelly, with the added bonus of involvement in and profit from Libya’s oil industry.

The trench was dug by Russian-backed mercenaries Wagner.