Thirty-six men whose bodies were found dumped beside a road near the city of Benghazi were killed in a "terrorist act" and the killers will be "found and punished", the Government of National Accord's (GNA) justice ministry has said.
GNA further added the crime "hindered the chances of the establishment in Libya of the rule of, justice and human rights."
The bodies found in the Al-Abyar district were reportedly marked with shots to the head and showed signs of torture. The UN-backed government sent its condolences to the families of those murdered and called on the public prosecutor's office to investigate.
However, since the public prosecutor Sadiq Al-Sour does not hold any power beyond the capital, Tripoli, it is unlikely the crimes will be aptly investigated as has been the case for the last few cases of mass killings in Libya over the last two years.
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UNSMIL Chief Ghassan Salamé "condemned in the strongest terms the heinous crime resulting in the killing of at least 36 whose bodies were found in the Al-Abyar area" and also called for an immediate investigation and for the perpetrators to be brought to justice.
He added: "There have been many cases of this nature in the last two years, yet no accountability."
The Libyan National Army (LNA) lead by Field Marshal Khalifa Haftar has also vowed it will investigate the mass murders but has in the past been slow in investigating criminals.
Earlier this year Haftar, who controls the east of the country which does not recognise the GNA in Tripoli, was pressured to investigate a case of mass executions after a video surfaced of Saiqa Special Forces Major Mahmoud Werfalli executing prisoners dressed in orange.
The execution was blasted as a war crime and the International Criminal Court issued an arrest warrant for Werfalli's arrest which the LNA has failed to help with.
Since the ICC's warrant, the LNA has banned military units from posting information of their activities on social media sites without first clearing it with the LNA so as to prevent videos being uploaded that show criminal behaviour.