Rebel forces loyal to Libyan General Khalifa Haftar on Sunday took control of the town of Sorman, 80 kilometres from the capital Tripoli, and took up positions in the city centre, security sources have reported.
Sources said that the Dawn of Libya militant group, which had previously controlled the city, withdrew towards Tripoli.
Sorman is a link between the city of Tripoli and the Ras Jedir border crossing between Libya and Tunisia.
Airplanes affiliated with Haftar's forces are reported to have launched airstrikes against Dawn of Libya sites in Al-Hashan and Bawabet Al-Sahlah amid violent clashes with tribal forces in several areas in the west of Libya.
The United Nations has been leading intense efforts since September last year to resolve the security and political crisis in Libya.