The UN is urging Libyan authorities to investigate a video circulating on social media of a group of Egyptian labourers being abused.
In the video the Egyptian workers are being made to stand on one leg and raise their hands in the air whilst cursing the Egyptian President Abdel Fattah Al-Sisi and Libyan commander Khalifa Haftar.
"UNSMIL is concerned about the arrest, detention and ill-treatment of a large number of Egyptian nationals," the UN mission tweeted.
The UN mission called on Tripoli authorities to investigate acts potentially in violation of "Libya's international human rights law obligations on the prohibition of torture, inhuman and degrading treatment or punishment," according to AFP.
Libya has two opposing governments, the UN-backed Government of National Accord (GNA) based in Tripoli and headed by Prime Minister Fayez Al-Sarraj and its rival led by the military commander Khalifa Haftar based in Tobruk in the east of the country.
Along with the UAE and Saudi Arabia, Egypt is one of the most prominent supporters of Haftar in the region. Since 2014 Egypt has provided significant political, military and logistical support to his Libyan National Army.
A spokesman for Haftar said the Egyptian men were being held by a GNA militia.
The Arab League have also condemned the detention and mistreatment of Egyptian nationals.
The GNA has said it will launch an investigation into whether or not the video is authentic and attempt to identify the perpetrators.
"Such occurrences should not spoil the strong relations between the Egyptian and Libyan people," the Interior Ministry said in a statement.
According to the foreign affairs minister of Libya's eastern government there are around 10,000 Egyptian workers in Libya, many of whom are illegal having been smuggled across the border and therefore are not protected against abuse or trafficking.