Libyan militias kidnapped several protesters after opening fire on a demonstration in Tripoli against economic conditions and corruption, the country's government in Tripoli said on Thursday.
Amnesty International said least six protesters were abducted when armed men allied with the Government of National Accord fired live ammunition to disperse a demonstration in the capital on Sunday.
The GNA said an investigation had been opened after the militias, which it did not identify, abducted some of the protesters.
The Interior Ministry acknowledged that a Tripoli-allied militia fired live ammunition at peaceful protesters.
The protesters in Tripoli “did not obtain necessary permits" for the rally, GNA Prime Minister Fayez Al Sarraj said on Monday as demonstrations continued in the capital and western Libyan towns.
In a meeting with military and security officials on Wednesday, Mr Al Sarraj announced a 24-hour curfew lasting four days that he said was to contain the spread of coronavirus.
Protesters defied the curfew and took to the streets of Tripoli again late on Wednesday.
Militiamen opened fire again at Martyrs Square, the scene of Sunday’s attack, a protester told AP.
Amnesty said several protesters were wounded in the shooting on Sunday, which happened in an area under control of the Nawasi militia, which nominally operates under the GNA.
Amnesty said there were “strong indications that this militia was behind the attack” on the protesters.
Diana Eltahawy, Amnesty’s deputy regional director, criticised Mr Al Sarraj's government for not reining in "abusive, unaccountable militias and armed groups", instead “relying on them for security, law enforcement and fighting its rivals”.
Ms Eltahawy called for the immediate release of those abducted and an independent investigation.
The UN Support Mission in Libya on Sunday called for "those arrested to be handed over to relevant judicial institutions and for those who are arbitrarily detained to be released immediately".
The protests over poor living conditions, shortages of electricity and water and a lack of services began days after the GNA called for a halt to fighting between its forces and those allied to a rival administration in eastern Libya.
In a statement issued on Friday, Mr Al Sarraj also called for the demilitarisation of the central coastal city of Sirte, held by the Libyan National Army led by Field Marshal Khalifa Haftar.
An LNA spokesman on Sunday dismissed the ceasefire offer, saying warships sent by GNA ally Turkey were approaching Sirte to support an attack by Tripoli-allied militias, despite international condemnation of Ankara's interference.