Human Rights Watch accused the forces of retired Major General Khalifa Haftar of planting explosives and anti-personnel landmines as they withdrew from the southern neighborhoods of the city of Tripoli at the end of last month.
Human Rights Watch director of arms, Steve Goose, said that the use of landmines is unacceptable under international law.
Human Rights Watch called on Haftar to publicly pledge not to use mines, and to instruct the fighters under his command and the foreign fighters supporting him, to desist from using mines and destroying any stockpiles of them.
The organization added that the recent use of landmines would add an additional burden to Libya, which suffers from uncleared landmines and unexploded ordnance, which would pose a threat to Libyans for years to come.
On May 25, the United Nations Support Mission in Libya expressed concern about reports of the killing or wounding of residents of Ain Zara and Salah al-Din neighborhoods in Tripoli with improvised explosive devices placed in or near their homes.
A video clip showed several explosive devices used in house-hunting, including anti-vehicle mines, paired with different types of detonating valves and a mixture of electronic timers, circuit boards, and modified cell phones.
Human Rights Watch said that these devices were assembled and used in a manner intended to detonate them as soon as a person was present, approaching or coming into contact with them, and was able to inflict disability, injure or kill one or more persons.