A riot erupted at a western prison Wednesday, leaving 10 inmates dead and one wounded a day after authorities seized weapons and illegal drugs from gang members in the jail, an official said.

Deputy Justice Minister Yuri Pimentel said authorities suspected anger over the weapons seizure might have set off the violence at Santa Ana prison in Tachira state.

"The situation at the prison is now under total control," he told state-run television.

Pimentel didn't say whether authorities used force to regain control, but he attributed all the inmate casualties to fighting among the prisoners.

Like many prisons in Latin America, Venezuela's jails are notoriously overcrowded and undersupervised. Firearms, illegal drugs and knives are often smuggled into jails by families of inmates or sold to prisoners by guards.

Pimentel said authorities seized four revolvers, two semiautomatic pistols and dozens of bullets along with cocaine, crack and marijuana during a search of the prison Tuesday.

"We have weaknesses in the security measures at these institutions," he said.

He also said lack of space means prisoners held on less serious crimes are often put together with dangerous criminals, "and this has an influence on these kinds of events."

Pimentel said prisons also are tense because roughly 40 percent of the inmates are still awaiting trial. In some prisons, inmates have seized control of cellblocks or taken hostages to demand their cases be dealt with more quickly.

Violence is common in the country's 30 prisons, which were built to house 15,000 inmates but house around 20,000.

Some 280 inmates died in violence and at least 449 were injured during the first nine months of 2005, according to the Venezuelan Prisons Observatory, a human rights watchdog. For all of 2004, at least 327 inmates were killed and 655 were wounded, the group says.