"The evacuation of prisoners from the Uribana jail has concluded. Now for reconstruction," Prisons Minister Iris Varela announced on her Twitter feed.

Varela said the final prisoners left quietly "without any resistance," posting to the social network a photo of several inmates with military officials.

The minister had admitted to reporters Saturday that the government "was not in control of all of the area of the Uribana penitentiary" in Lara state, a day after clashes erupted between prison gangs and guards.

She said the rioters and other inmates were being moved to other prisons around the country.

Meanwhile, relatives of inmates missing after the deadly violence were desperately seeking news of their loved ones.

"I don't know if my son is alive or dead behind those big doors," said Elvira Rodriguez, weeping and waiting for her son Joseph, who has spent two years awaiting trial for kidnapping.

"I have looked for him in all the hospitals."

Most of the 61 killed at the Uribana facility on Friday were shot by assault weapons. Antonio Maria Pineda Hospital director Ruy Medina said in an updated toll that another 120 people were wounded.

The toll was expected to climb as more information emerged about the battle to recover control of the penitentiary. Officials said it was "very probable" that the final results of the operation would be announced Sunday or Monday.

National Guard troops earlier surrounded the Uribana prison as inmates in bloody clothes were taken out of the building and as distraught relatives waited for news behind the barriers.

Dozens more lined up waiting for death certificates.

Carmen Garcia was seeking word on her son, who had been brought back to the prison after being treated in a hospital for a bullet wound.

"We just cannot find anybody who will give us an explanation," said the woman of about 50, who was among about 200 relatives.

"It was like a war movie here with tanks rolling and shooting and so much smoke," she said.

Linelida Alvarez was equally anxious to find out the fate of her brother, 21-year-old Carlos Eduardo, but braced for the worst.

"We don't know anything," Alvarez told AFP. "They told us he had received a shot in the chest. But the question is why are there so many people who have been slaughtered. There are many people with firearm wounds."

Vice President Nicolas Maduro, just back in the country after visiting ailing President Hugo Chavez in Cuba, called the riot "regrettable" and "tragic," and said an investigation had been launched.

The Uribana prison is believed to hold about 2,500 inmates.

Opposition parties immediately accused the government of exercising lax control over the prison system.

"Who will they blame for this massacre this time around?" opposition leader and former presidential candidate Henrique Capriles said on Twitter, calling the government "incapable and irresponsible."

Humberto Prado, head of the non-governmental Venezuelan Prison Monitoring Organization, said the government "had failed to take responsibility for the events" and instead was "piling blame on the media."

Venezuela is notorious for the poor state of its prisons, which suffer from some of the most staggeringly high levels of overcrowding in Latin America.

Originally built to house 14,000 inmates, the country's prisons now hold almost 50,000 people, often with low sanitary standards and high levels of violence.

In August 2012, at least 25 people were killed and 43 wounded during a clash between rival gangs in Yare I prison near Caracas. In June 2011, dozens died in a riot that erupted at El Rodeo prison.