More than 20 people were killed in a prison riot as two groups of inmates waged a gunbattle inside the jail, Venezuelan officials have said.

The violence erupted on Sunday at Yare I prison south of Caracas, and one of those slain was a relative of an inmate, said Iris Varela, the government's prisons minister, on Monday.

It was the latest in a series of bloody clashes that have erupted inside Venezuela's overcrowded prisons and become a major problem for President Hugo Chavez's government.

Varela told state television that more than 20 people were killed, but did not give a precise death toll or explain how the riot broke out. She said that as of Monday morning the situation at the prison was under control.

Varela said those behind the killings "are going to have to answer for this". She did not provide details about how the inmate's relative died.

'Prison problem'

Carlos Nieto, an activist who monitors human rights in Venezuelan prisons, said another relative who was inside the prison told him the shootout began during family visiting hours.

Nieto said the gunbattle lasted about four hours and involved groups fighting for control.

Nieto said the riot shows that the "most serious prison problem, the weapons possessed by inmates, hasn't been solved".

He noted that less than a month ago, another bloody riot erupted at another prison in Merida state.

Violence has proliferated inside Venezuela's prisons, where inmates often obtain weapons and drugs with the help of corrupt guards.

The watchdog group Venezuelan Prisons Observatory says 560 people were killed in Venezuelan prisons last year. It also says the pace of the violence increased during the first half of this year, with at least 304 inmates killed.

Venezuela currently has 33 prisons built to hold about 12,000 inmates, but officials have said the prison population is closer to 47,000. Hundreds are held in Yare I, though a precise count wasn't immediately available.

Renovations promised

Following a deadly armed uprising last year in the prisons El Rodeo I and El Rodeo II, just outside Caracas, Chavez announced plans for changes to the country's troubled penal system, including the construction of new prisons, better conditions and quicker trials for inmates who have yet to be sentenced.

Since then, Chavez has approved funds to repair and renovate prisons. Varela said the government has started activities for inmates, allowing them to attend classes and to prepare food that they sell.

Chavez's political opponents and groups which monitor inmates' rights have criticised the government's response as inadequate, and outbursts of violence continue to erupt.

In one case in May, the government shut down Caracas' La Planta lockup and moved inmates to other prisons following a three-week uprising that pitted armed inmates against troops.

Officials said one man who lived near the prison was hit by a stray bullet during the shootout and died, and that five others were wounded.

Source: Associated Press