Updated

The United Nations says it is appalled by reports of "retribution killing" in eastern Libya.

Friday's statement by the U.N. Support Mission in Libya comes after reports emerged on the killing of five people in Benghazi and three in Darna.

Grisly photos circulated online showed bodies left on a roadside in Benghazi. The photos' authenticity couldn't be independently verified. It is unclear who was behind the killings.

Local media including al-Wasat news portal reported that the extremist Mujahideen Shura Council was behind the killings in Darna.

"The brutal pattern of violence must end," the U.N. mission said. "Those in effective control of fighters and those ordering, committing such crimes are liable under International law."

Libya descended into chaos after a 2011 uprising that toppled and killed longtime dictator Moammar Gadhafi.