Libya’s UN-backed government has mobilized its troops toward the strategic city of Sirte, which is controlled by warlord Khalifa Haftar’s forces.
UN officials say Haftar’s Libyan National Army has blockaded major oil fields and ports, shutting off most of the country’s oil production.
The deployment by the Government of National Accord came as representatives from Libya’s rival factions gathered in Geneva for talks.
The talks were aimed at securing a ceasefire following 10 months of fighting on the outskirts of the capital Tripoli.
The conflict started in April after Haftar’s forces launched an offensive to take control of Tripoli.
Tens of thousands of people have been displaced by the violence.
Since 2014, Libya has been divided between two rival camps — the Tripoli-based government of Prime Minister Fayez al-Sarraj, and a camp in the eastern city of Tobruk, supported militarily by Haftar’s forces.