Ethnic clashes between rival gunmen from the Toubou and Tuareg minorities has left at least 40 people dead in a week in southern Libya, a local official said.
The latest fighting centred on the oasis city of Sabha, the largest in the Libyan Sahara, the official said. Hundreds of families have been displaced, he added.
There have been repeated deadly clashes between the two ethnic groups since February.
The Toubou, who mainly live in the southeast straddling the border with neighbouring Chad, were heavily discriminated against under dictator Moamer Kadhafi and fought in the 2011 uprising that overthrew him.
The Tuareg, who mainly live in the southwest straddling the borders with Algeria and Niger, largely backed the Kadhafi regime.
The chaos that has followed the uprising has seen mounting competition for scant resources in the desert south, with Tuareg, Toubou and Arabs all setting up rival militia.
Deadly fighting with Arabs in Sabha in 2012 prompted Toubou claims of ethnic cleansing.
Tensions have worsened since the establishment of rival governments in the capital Tripoli and the eastern town of Tobruk last year.
The Tripoli authorities have armed the Tuareg while the Toubou have backed the internationally recognised government in the east.
The Tobruk government issued a statement on Tuesday appealing to the warring sides sides to “stop fighting and resolve their differences through dialogue”.