Some 400 prisoners have escaped from a facility near the Libyan capital Tripoli amid deadly violence between militia groups in the city, police say.
"The detainees were able to force open the doors" in order to leave the Ain Zara prison, the local police said.
They added that guards, fearing for their lives, were unable to prevent the breakout following riots at the jail.
Clashes between militias in the city have led Libya's UN-backed government to declare a state of emergency.
The incident on Sunday took place during armed violence between rival factions around the facility, which houses only male inmates.
Many of the prisoners held at the Ain Zara prison in south-east Tripoli were reportedly supporters of the late Libyan leader Muammar Gaddafi, and had been found guilty of killings during the uprising against his government in 2011.
Separately on Sunday, two people were killed and several others were injured when rockets hit a camp in Libya's capital housing hundreds of displaced people, according to emergency services and witnesses.
Libya's Ministry of Health reports that some 47 people, including civilians, have died in rival militia clashes in Tripoli over the past week, with dozens more injured. A UN-backed government is nominally in power in the capital, but militias occupy much of the rest of the country./BBC