The Tripoli-based Judicial Police Authority ‌said in a statement that the mass escape happened at Surman jail and that it had launched an investigation into the incident.

Police did not reveal ​the exact number of inmates who escaped from the jail, adding that it formed ​a committee to "identify them and take necessary legal action ⁠against them."

Salem Bahr, a local leader in the town of Zawiya, appealed via ​Turkey-based Libya Al-Ahrar TV channel for an end to the fighting because "everyone who ​wins in this situation loses."

Bahr said the clashes killed three civilians and injured several others.

There was no immediate indication of who had taken part in the violence ​or why they were fighting. Libya has been plagued by unrest ​since the overthrow of Muammar Gaddafi in 2011.

The clashes took place in Zawiya ‌and ⁠Surman between rival armed groups. Zawiya, 40 km (25 miles) west of Tripoli, is home to Libya's largest functioning Azzawiya refinery, with a capacity of 120,000 barrels per day.

Azzawiya Oil Company put out a ​statement on Facebook ​urging workers "to ⁠take maximum precautions and completely avoid areas of clashes and the roads leading to them."

Unverified footage on ​the internet and local TV channels showed large plumes of ​black smoke ⁠billowing in the sky, and other clips contained heavy gunfire across Surman and Zawiya.

The mayor of Surman, Mohamed Abu Snina, described the humanitarian situation as ⁠very ​bad and said the clashes had ​caused serious damage, stressing that relative calm had returned to the city after the deployment ​of a neutral force.