A mass grave with at least 36 bodies has been uncovered near Benghazi in Libya.
The victims appear to have been executed, but it is unclear who they are. One report says some of the bodies were dressed in business suits while others were wearing athletic clothes.
Ghassan Salame, the head of United Nations mission in Libya, said in a statement he was "appalled by this heinous crime" and called for an investigation and greater accountability for cases of this nature.
Both of Libya's rival administrations – the internationally recognized government in Tripoli and the one in the east led by strongman Khalifa Haftar – also condemned the killings and promise to investigate.
Haftar's fighters are suspected in a number of killings over the past three years.
Libya has been in chaos and political turmoil since longtime strongman Moammar Gadhafi was toppled and killed in 2011.
A U.N.-backed unity government in Tripoli has struggled to assert its authority over the numerous militias battling for territory on the ground.