New fighting broke out in southern Libya on Saturday between members of the Toubou minority and government forces, the two sides said, with unconfirmed reports that at least five people were killed.
Tribal chief Issa Abdelmajid said the Toubou quarter of the town of Kufra came under shelling at 3:00 am (0100 GMT) by the Libya Shield Brigade, former rebels under government control sent to quell previous ethnic fighting.
Abdelmajid said at least five of his people were killed and 10 wounded, and that a number of houses in the quarter had been burned.
Brigade commander Wissam Ben Hmid confirmed the fighting, saying his men had responded to a Toubou attack on one of their checkpoints.
He said three of his men had been wounded.
In February, clashes pitting the Toubou against the rival Zwei ethnic group in Kufra cost more than 100 lives and displaced half the population, according to UN figures.
Libya's nascent army intervened by sending the brigade from the eastern city of Benghazi to uphold a hard-won ceasefire.
Kufra, a town of about 40,000, is located in a triangle where the borders of Egypt, Chad and Sudan meet.
In April, fighting between the Toubou and the brigade killed 12 people.