Forces loyal to putschist Gen. Khalifa Haftar are detaining at least nine "peaceful protesters," Amnesty International said on Tuesday.
Those being detained were among about 30 people who protested last month in Sirte, the hometown of deposed dictator Moammar Gadhafi.
Amnesty said the demonstrators called on international and local authorities to compensate victims of NATO airstrikes during the 2011 revolt that overthrew Gadhafi.
The detention of several protesters and a Libyan TV reporter who covered their rally reflects how rights have been "brutally crushed" in areas under the control of Haftar-affiliated forces, an Amnesty press release said.
Sirte, in the center of Libya's Mediterranean coast, has been controlled by pro-Haftar forces since 2020.
"The arbitrary detention of these peaceful protesters for demanding justice and reparation in connection to the 2011 armed conflict shows just how intolerant LAAF and affiliated armed groups are of any independent activism, even if not critical of their rule," Diana Eltahawy, Amnesty's deputy director for the Middle East and North Africa, said in the press release. LAAF is an acronym for Haftar's self-proclaimed Libyan Arab Armed Forces.
"Suspected opponents and critics have either been gunned down in the street, forcibly disappeared or are languishing in jail," Eltahawy said.
Last month United Nations investigators said serious rights violations including possible crimes against humanity were continuing with impunity across much of Libya, blocking the country's transition to peace and democracy.
Since early March Libya has found itself with two governments after the eastern-based House of Representatives appointed ex-Interior Minister Fathi Bashagha in a challenge to the Tripoli-based prime minister, Abdul Hamid Dbeibah.
Bashagha is allied with Haftar, whose external backers include Russia. Dbeibah, installed last year as part of a U.N.-led peace process, has insisted he will only cede power to an elected administration.
Presidential and parliamentary elections set for last December were indefinitely postponed.