At least 11 prisoners have been killed in gang-related violence in one of Venezuela's largest jails, officials say.
The dead men were hacked and shot to death by prisoners armed with pistols, knives and shotguns at the Yare 2 prison in the central state of Miranda, about 40 kilometres (25 miles) south of the capital, Caracas, they said.
At least two inmates were reported to have been decapitated. A further 40 prisoners were injured.
Prison authorities quelled the riot after calling in national guard troops and police to restore order to the jail complex.
It is not clear how the disturbance started.
The police say they intervened to stop a violent clash between two rival gangs of prisoners, but some of the inmates' relatives said it was the police who started the riot.
The Yare 2 prison complex, which holds about 1,200 prisoners, once held current Venezuelan President Hugo Chavez after he led a failed coup in 1992.
Last month, inmates at the prison went on hunger strike to protest conditions at the complex and continual delays in trial processing, French news agency AFP reports.
Correspondents say violence is common-place in Venezuela's over-crowded and poorly-regulated prisons, with a series of major riots taking place in the last few years.
More than 200 prisoners were killed and more than 1,200 injured in violence within the Venezuelan prison system between October 2001 and September 2002, according to statistics from the Venezuelan ministry of interior and justice.