A UN human rights team set up to investigate rights violations in Libya said on Monday it was concerned about allegations that many black Africans were being illegally detained in Libya.
"In recent weeks, reports have emerged of the mass arrest of black Africans who are suspected of being pro-Gaddafi mercenaries," Philippe Kirsch, a member of the International Commission of Inquiry on Libya told the Human Rights Council.
"It has been reported that large numbers of migrant workers from Chad, Mali, Niger, Nigeria and Sudan have allegedly been arbitrarily arrested by security forces of the NTC in Tripoli," he said.
Kirsch said that the detainees were reportedly being held in prisons at Ain Zara, Tajouran and the Mitiga Airbase, as well as temporary detention facilities at the National Oil Institute, the Bab al-Bahr football club and local schools.
"There are also allegations that dark-skinned Libyans have also been arbitrarily arrested and detained," Kirsch said, adding that many had not yet been brought before a judge to review the legality of their detention.
The 47-member UN Human Rights Council set up the investigative team in February at the beginning of the conflict between Muammar Gaddafi's regime and rebels.
After visiting Libya, neighbouring Egypt and Tunisia during the first half of the year, Kirsch said the investigative team was planning to go to Tripoli, western Libya and Benghazi in the latter part of 2011 and January 2012.
Previously, the International Organisation for Migration had also warned that people of African descent were being targeted in Libya.
Last week, it said it had begun evacuating over half of around 2,000 sub-Saharan Africans who are stranded in the town of Dirkou in neighbouring Niger, after having fled fighting in Libya.
"There has been a surge in sub-Saharan Africans arriving, largely citing the targeting of Africans as the reason for leaving," an IOM spokeswoman said.