Members of Libya's Toubou minority and government forces fought for a second consecutive day on Sunday, with the death toll rising to 23, tribal sources and a local military commander said.

Doctor Taher Wehli said 20 members of his Toubou community, including women and children, were killed since fighting erupted in Kufra on Saturday, with more than 50 other people wounded.

Wissam Ben Hmid, commander of the Libya Shield Brigade which is stationed in the southern oasis city, said he had lost three of his men in fighting sparked by a Toubou attack on one of their checkpoints.

He said twelve others members of the brigade -- former rebels under government control which were sent to quell previous ethnic fighting -- were wounded during clashes.

But tribal chief Issa Abdelmajid gave a higher toll saying 28 people were killed in two days of fighting that erupted on Saturday when the Toubou quarter of the town of Kufra came under shelling by the Libya Shield Brigade.

"Twenty-eight dead since yesterday," Abdelmajid told AFP.

The controversial tribal chief accused the government brigade of trying "to exterminate" the Toubou minority and urged the United Nations to pressure the ruling National Transitional Council to "break the siege against the Toubous."

Another tribal leader in the southern oasis city confirmed that more than 20 people had been killed in Toubou areas.

"The situation in Kufra is critical," said Hussein Sake.

He noted that there were no major hospitals in the area and that medics at a basic clinic were struggling to treat the wounded because there was no blood for transfusions.

He also accused the Libya Shield Brigade of pounding Toubou areas.

"The attack isn't over yet," he said.

Ben Hmid also confirmed that fighting continued on Sunday.

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.