The Libyan Interior ministry says it had arrested the three men who allegedly burnt a Nigerian man to death.
It said the suspects had used petrol to set the victim on fire at a factory.
Federico Soda, Libya country Chief for the International Organisation for Migration (IOM), a U.N. migration agency, said those responsible must be held accountable.
The IOM and the U.N. refugee agency UNHCR have both repeatedly said that Libya should not be classified as a safe port for migrants.
The three Libyans according to report, killed the Nigerian man by setting him on fire in Tripoli, the interior ministry said on Wednesday, in what a U.N. agency described as another senseless crime against migrants in the country
IOM said there are half a million migrants in Libya, some of them having worked in the oil producing country before it descended into chaos and warfare, while others are attempting to travel through it to Europe.
Reports said thousands have attempted the perilous sea crossing to Europe this year, with hundreds drowned in shipwrecks.
According to the report, in July, three migrants from Sudan were shot dead by Libyan authorities while trying to flee detention after they were disembarked in Khums.
Also in May, 30 mostly Bangladeshi migrants were shot dead in a southern desert town after being abducted by a local gang.
The Chairman/CEO, Nigerians in Diaspora Commission, Abike Dabiri-Erewa, has condemned the killing, describing it as dastardly, bestial and unacceptable.
Honourable Dabiri-Erewa called on the Libyan Authorities to apply the full weight of the law on the suspected Killers.
In the meantime, the full identity of the Nigerian man set on fire by petrol has not been made known as investigations and interrogations of the suspected attackers who are in custody are ongoing.
