Relatives of prisoners killed on the eve during clashes at a police station jail in Acarigua

Wracked with pain and anger, dozens of families gathered in front of a morgue in the Venezuelan town of Acarigua on Saturday after 29 inmates died in rioting at a police station jail.

"It seemed there was a massacre of these children in the police station," 50-year-old Zuleyma Ponte told AFP.

"My son was killed. Whose fault is it? It's the lack of supervision, the lack of serious government," he said.

The deaths came after police special forces intervened Friday to stop a "massive prison break," according to Oscar Valero, public security secretary for Portuguesa state.

The prisoners received the officers with "a hail of gunfire" while detonating three grenades that wounded 19 police, Valero told reporters.

As the clash raged, family members near the station said they heard detainees shouting, "Don't let us die."

"What we are asking for is, please, just give us our boys. They're not coming back, so give their bodies to their families and investigate those responsible," said Aliris Perez, a 34-year-old teacher whose 24-year-old brother died in the violence.

Perez, who was close to the station when the riot occurred, said he heard several explosions as "many authorities" arrived at the site.

Carlos Nieto, the head of a prisoner rights NGO, said the clashes broke out when special forces attempted to rescue visitors who had been taken hostage Thursday by the leader of the inmates.

An official of the National Service of Medicine and Forensic Sciences told VPI online television on Saturday that work in the morgue was delayed as they waited for supplies from the capital Caracas, about 350 kilometers to the east.

"They're sending us supplies, gloves, gowns, autopsy boots and scalpels, all of which we didn't have," said the official, whose name wasn't given.

Eight autopsies have already been carried out, the official said.

Overcrowding common

Violence and overcrowding are common in the approximately 500 preventative detention centers in Venezuela.

The penal code says defendants should not spend more than 48 hours in these centers, but in practice they function as prisons, and it's often unclear who is responsible for them.

In the Acarigua police station, there were about 500 inmates in a space built for 60, according to an internal police report seen by AFP.

Bloody clashes and accidents often occur in the facilities.

In March 2018, 68 inmates died in a fire at a police jail in the northern city of Valencia, and in August 2017, a riot at a facility in the southern Amazonas state left 37 prisoners dead.

More than 400 people are believed to have been killed in Venezuelan jails since 2011, while human rights organizations also say they face a lack of food and medicines -- like much of the country -- while the facilities are beset by corruption.

Following the bloodshed in Acarigua, the Inter-American Commission on Human Rights expressed its "special concern for the high levels of violence in Venezuelan prisons," and called for authorities to "protect the life and security of people under its custody."

Amnesty International Americas director Erika Guevara-Ross blamed the Venezuelan government, writing on Twitter that, "because these people were under the custody of the state... the government of (President) Nicolas Maduro is principally responsible for these deaths."