BARQUISIMETO, Venezuela (AFP) - Security forces regained full control over a prison in north-western Venezuela on Sunday and evacuated inmates after a riot left 61 dead and twice as many wounded.

"The evacuation of prisoners from the Uribana jail has concluded. Now for reconstruction," Prisons Minister Iris Varela announced on Twitter, adding that the last prisoners left quietly "without any resistance."

It took authorities two days to regain control of the entire Uribana penitentiary in Lara state after clashes between prison gangs and guards. Ms Varela said rioters and other inmates were being moved to other jails around the country.

Some inmates shouted from moving buses the names of the jails they were being moved to as worried-looking relatives waved goodbye.

"My brother is going to Guanare," in north-western Venezuela, said Carmen Escalona, sister of Jose, 32, who she said is serving four years as an accomplice to a friend who robbed a taxi driver.

"It's not the same as having him nearby, but where he goes, the fight will go," she said.

Meanwhile, some family members of inmates still did not know the fates of their loved ones after the deadly violence.

"My son has been missing since Friday. He appears on lists of wounded and I have looked for him," cried Mariela Torrealba, weeping, as she searched in vain for information on the whereabouts of her son Henry, 24.

"This is a hopeless anguish," she sobbed.

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," Ms 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." Most of the 61 killed at the Uribana facility were shot by assault weapons.

Antonio Maria Pineda Hospital director Ruy Medina said in an updated toll that another 120 people were wounded.

Authorities said the riot was sparked by an inmates rebellion when the prison launched a sweep of the facility in search of illicit weapons, after receiving a tip-off that prison gangs were readying to fight.

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

Opposition leaders and watchdog groups denounced what they said was a "disproportionate use of force" and the failure of the prisons ministry, created in mid-2011, to violence and overcrowding.

"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."

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.

Uribana is believed to hold about 2,500 inmates.

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, 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.