ADDIS ABABA, Ethiopia — Libyan rebels may be indiscriminately killing black people because they have confused innocent migrant workers with mercenaries, the chairman of the African Union said, citing the fears as one reason the continental body has not recognized opposition forces as Libya’s interim government.

“NTC seems to confuse black people with mercenaries,” AU chairman Jean Ping said Monday, referring to the rebels’ National Transitional Council. “All blacks are mercenaries. If you do that, it means [that the] one-third of the population of Libya, which is black, is also mercenaries. They are killing people, normal workers, mistreating them.”

He added: “Maybe it’s looters, uncontrolled forces. But then the government should say something, condemn this. We want to see a signal that the African workers that are there, they should be evacuated.”

Ping’s comments follow concerns from international rights groups about beatings and detentions of immigrants from sub-Saharan Africa.

“I really fear vigilante justice and retribution and attacks by civilians against other civilians,” said Richard Sollom, deputy director of Physicians for Human Rights, who is back from a June fact-finding mission in Misrata, Libya.

Sollom said Monday that his Boston-based group knew of about 500 Darfuris “who are desperately trying to get out of Libya. They have no money, they are basically homeless because they are from Darfur, and they very much fear for their lives because of the color of their skin.”

Guest workers from Sudan, Chad, Darfur and other sub-Saharan African locales have been targeted in part because Gadhafi did hire foreign African mercenaries, Sollom said.

Reporters for The Associated Press have witnessed several episodes of rebels mistreating detainees or sub-Saharan Africans suspected of being hired Gadhafi guns, including an incident where about a dozen black men were detained and some were punched.

Ping said the AU will work with the U.N. and any other partners, including NATO, to find a political solution for Libya that leads to democracy.