A Libyan TV channel on Wednesday aired a footage of detention places where opponents were tortured by warlord Khalifa Haftar's militia in Tarhouna city, southeast of Tripoli.
The video clip broadcast by the private February channel shows extremely narrow cells where prisoners can hardly sit inside in a squatting position.
The footage has sparked outrage on social media, with one user saying the cells looked like "Nazi concentration camps", while another described them as "Libya's Holocaust".
On Tuesday, the International Criminal Court agreed to dispatch an investigation team to look into Haftar's militia crimes in Tarhuna city.
The UN also said in a statement that landmines planted by Haftar's forces have killed and wounded 138 persons within two months.
In addition to the landmines' crimes, mass graves for more than 200 persons were discovered in places that were under Haftar's militia control in Tarhuna.
Since April 2019, Haftar's illegitimate forces have launched attacks on the Libyan capital of Tripoli and other parts of northwestern Libya, resulting in more than 1,000 deaths, including civilian women and children.
However, the Libyan government has recently achieved significant victories, pushing Haftar forces out of Tripoli and strategic city of Tarhouna.