A riot last week at Uribana prison in the western state of Lara left 58 people and around a hundred others injured, the head of Venezuela's penitentiary service said.
All but 161 of the nearly 2,500 inmates have been transferred to other prisons since Friday's violence, Iris Varela said in a televised press conference.
Ruy Medina, director of Central Hospital in Barquisimeto, Lara's capital, told Efe on Saturday that 61 people died at the prison.
The fatalities included a Protestant pastor and a member of the National Guard unit dispatched to secure the prison grounds, Varela said from Uribana.
Forty-six of the injured remain hospitalized, while 49 others were treated at the scene, the prisons minister said.
The casualties did not result from a clash between inmates and authorities, she said, but were rather the work of hidden "negative leaders" inside the prison who emerged sporadically to shoot people "at point-blank range."
"There was resistance in the face of what was imminent, which was that we were preparing to carry out an inspection in complete peace," Varela said.
Besides evacuating Uribana, authorities will undertake an "exhaustive review" of the cases of all the inmates with an eye toward granting parole or pre-trial release to anyone who qualifies, the minister said.
In Venezuela, as in other Latin American countries, defendants often spend months or even years behind bars awaiting trial.
Violence inside the Andean nation's overcrowded penal institutions claimed 864 lives between Jan. 1, 2011, and June 30, 2012, according to figures from the independent Venezuelan Prisons Observatory. EFE