Published by New York Times

William Neuman reported from Caracas, and Girish Gupta from Barquisimeto, Venezuela.

Dozens of people have been killed in fierce clashes between inmates and National Guard soldiers at a Venezuelan prison, local news media accounts said Saturday.

It was the latest in a series of riots over the past year in overcrowded prisons, where guns and drugs abound and inmates control many aspects of life.

Newspapers initially reported that more than 50 people had been killed at the Uribana prison in Barquisimeto, a northwestern city, citing the director of a hospital where the wounded and the dead were taken. Later Saturday, the director, Ruy Medina, said that the number of dead had risen to 61, and that 120 people had been injured, The Associated Press reported. He said nearly all the wounds were from gunshots.

The minister of prisons, Iris Varela, said the violence broke out Friday when troops entered the prison to search for weapons and establish order.

The situation remained chaotic on Saturday. Local news media reports said that most of the dead were prisoners.

“We are all afraid because we don’t want to die,” said a man who identified himself as an inmate inside the prison when reached Saturday by cellphone; it is typical for inmates here to have phones.

The 27-year-old inmate, imprisoned on a robbery charge, asked not to be identified for fear that speaking out could put him at risk. He said that many of the inmates remained inside the prison, although the dead and badly wounded had been removed.

“We are hiding here, waiting to find out what happens to us, for them to help us,” he said.

The prison violence poses a new test for the government as President Hugo Chávez remains in Cuba, where he has been for more than six weeks undergoing treatment for cancer. Top officials have been trying to show that the government is running smoothly, even as they grapple with uncertainty about the president’s health, a constitutional dispute over the start of his new term, shortages of basic goods and signs of resurgent inflation.

“There was a tragic situation of confusion that we lament very much,” Vice President Nicolás Maduro said Saturday, promising an investigation. He spoke after returning from Cuba, where he had gone to visit Mr. Chávez.

Ms. Varela said that officials decided to conduct the raid after receiving information that violence had increased between inmate factions vying for control.

But she said that word of the operation leaked out and that it was reported by a television station, a local newspaper and social networking sites.

Ms. Varela called the reports “a detonator of the violence.” She said that the dead had wounds from knives, firearms and explosives, and that some were killed before the troops arrived.

The Venezuelan Prison Observatory, a human rights group, said 560 prisoners were killed in the nation’s prisons in 2011.

Last year, two major episodes left dozens dead: 25 people were killed at one prison, the government said, and 30 died in another, the Prison Observatory said.

Outside the Barquisimeto prison and a hospital on Saturday, hundreds of people, mostly inmates’ relatives, waited for news.

“This happens all the time and nothing changes,” said Yolanda Rodríguez, 57, who was waiting for information about her 24-year-old son, an inmate. “We know nothing about what’s happening inside.”