Human Rights Watch in February said authorities in Misurata weren't doing enough to stop local militias from harassing displaced people.
In its recent statement, the rights group warned that Misurata leaders could be brought before the International Criminal Court for serious crimes against humanity. The rights group said it had evidence to suggest militias in the former rebel capital were responsible for torture and forced displacement of area residents.
"Five months after the conflict with (Moammar) Gadhafi forces ended, militias from Misurata are still committing serious abuses -- crimes under Libyan and international law -- and the city's leaders can be held legally responsible for those acts by the ICC," Sarah Leah Whitson, Middle East director at Human Rights Watch, said in a statement.
Authorities in Misurata had told Human Rights Watch that some returning refugees had fought alongside pro-regime forces during the uprising last year.
Libya, following last year's NATO-led intervention, is threatened by various claims of autonomy and tribal clashes.