Victims of the clash at Uribana prison in Lara state began arriving at a local hospital around midday on Friday, according to the hospital director Ruy Medina. He estimated that at least 50 had been killed and 90 wounded in the incident.
Medina said that most of the injured had suffered gunshot wounds. He described the death toll as "alarming," adding that it was based solely on the number of bodies that had been brought to the hospital.
Violence broke out in the prison located in northwestern Venezuela on Friday morning when prison personnel were conducting an inspection for illicit weapons.
Television images showed troops surrounding the prison as inmates wearing bloody clothes were removed from the building. Initial reports indicated that the clash occured when inmates resisted the search.
"Due to violent occurrences in Uribana prison, an inspection was necessary to completely unarm the inmates," Penitentiary Service Minister Iris Varela told state television.
Varela said the operation had been launched because internal gangs fighting for control of the jail were trying to settle scores with each other.
Vice President Nicolas Maduro said early on Saturday that the authorities had launched an investigation and called the violence tragic.
However, former opposition presidential candidate Henriques Capriles blamed the government, claiming they were responsible for lax control of the prison system.
kms, rc/jm (AFP, dpa)