A fight between rival gangs in a prison in Venezuela has left at least 10 prisoners dead, reports say.
Inmates used automatic weapons and hand grenades in an eight-hour battle for control of Tocoron prison in Aragua state, Venezuelan media reported.
There has been no official statement on the violence, and families of prisoners have been demanding information.
Venezuela is suffering rising levels of violent crime, and bloodshed is frequent in its overcrowded jails.
The fighting in the Tocoron prison was triggered by the killing earlier this week of a gang leader who controlled one area of the jail, Venezuelan newspaper El Universal reported.
Police surrounded the prison as gunfire and explosions were heard inside.
Four women relatives of prisoners were wounded by stray bullets as they waited outside for news.
Prisoners' families blocked nearby roads in a protest to demand information about the fate of their loved ones.
The campaign group Venezuelan Prison Watch says more than 220 inmates died inside Venezuela's prisons in the first quarter of 2010 alone.
It says Venezuela's jail system has a capacity for 15,000 but currently holds around 40,000.
Many cell blocks are controlled by violent criminal gangs with links to drug trafficking.
Earlier this month thousands of inmates in jails across Venezuela, including Tocoron, joined a hunger protest to demand improved conditions and an end to alleged human rights abuses by guards.
The Inter-American Commission of Human Rights has urged Venezuela to take action to tackle violence and insecurity in its prisons, and to protect the human rights of inmates.