Caracas: At least 37 people died in an hours-long jail riot in Venezuela’s southern state of Amazonas, officials said Wednesday.

The prosecutors’ office said an investigation had been launched into “the deaths of 37 people” in the facility in the town of Puerto Ayacucho.

Governor Liborio Guarulla had earlier tweeted that a “massacre” took place with at least 35 corpses counted.

Prosecutors said 14 officials were wounded in the violence, but did not say if any were among the dead.

Two prison-monitoring groups, A Window to Freedom and the Venezuelan Prisons Observatory, said the 37 killed were all inmates.

“This is the worst riot we’ve had in a detention facility,” Carlos Nieto of A Window to Freedom told AFP.

“In this one, detainees are only supposed to be held for up to 48 hours, but there were prisoners who have been there for years,” he said.

The jail was holding 105 prisoners at the time of the riot, Guarulla said.