The head of Libya's Toubou tribe on Friday called for international intervention to halt what he called the "ethnic cleansing" of his people after deadly clashes in the southern oasis of Sabha.
"We demand that the United Nations and European Union intervene to stop the ethnic cleansing of the Toubou," said Issa Abdel Majid Mansur, a former opposition activist against the ousted regime of slain dictator Moamer Kadhafi.
He accused Arab tribes in Sabha of bombarding a power station providing electricity to several parts of southern Libya including Qatrun and Morzuk, both areas with a strong Toubou presence.
Telecommunications were also cut off, Mansur said, and added that "several" members of his tribe were killed on Friday.
Mohammed al-Sawal, the national security chief in Sabha, confirmed to television channel Libya Al-Ahrar that the power station had been hit.
Sawal added that a 24-hour truce agreed on Thursday was broken at 0930 GMT after fighters on both sides rejected it, and that renewed clashes broke out.
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According to a mediator, Ridha Issa, Sabha tribes broke the ceasefire by using heavy artillery to bombard the Toubou Tayuri district of the city.
Issa said Sabha fighters also refused to pull back from Ghodwa area, 20 kilometres (12 miles) south of Sabha, between Toubou positions and those of Arab tribes, to let neutral forces from the north serve as a buffer.
Eight people were reported killed and several wounded in clashes in Sabha on Thursday.
The first clashes erupted Monday after Arab tribesmen accused the Toubou of killing one of their people. The first three days of clashes cost more than 70 lives, Libyan government spokesman Nasser al-Manaa said on Wednesday.
The Toubou say they are defending themselves against attack by Arab tribesmen in the region, and have accused the Libyan authorities of backing those gunmen as part of a campaign of "ethnic cleansing."
The Toubou are black oasis farmers by tradition who also have connections beyond Libya's borders. They live in southern Libya, northern Chad and in Niger, and have previously denied having separatist ambitions.
The Toubou have also been involved in deadly clashes with another tribe in the Saharan oasis of Kufra, where ethnic groups are locked in a standoff over smuggling.