Libyan revolutionaries are holding an estimated 7000 prisoners who have no access to legal process because police and the courts are not functioning, according to a United Nations report.
The report by Secretary-General Ban Ki-moon is the first UN assessment of the situation in Libya since the end of the eight-month civil war earlier this year.
It says some of the detainees held in prisons and makeshift detention centres, most under the control of revolutionary brigades, may have been tortured.
Many of those being held are sub-Saharan Africans suspected of being mercenaries hired by the Gaddafi regime, the BBC reports.
Mr Ban says he believes the leaders of the new Libya are committed to building a society based on respect for human rights.
He says achieving this requires the earliest possible action, however difficult the circumstances.