A bloody riot erupted in a Venezuelan prison when National Guard troops clashed with inmates, and Venezuelan media reported that dozens were killed.
Vice President Nicolas Maduro called the violence tragic early Saturday on television and said the authorities had launched an investigation.
He and other officials did not give a death toll from the riot Friday at Uribana prison in the central Venezuelan city of Barquisimeto.
The newspaper Ultimas Noticias reported on its website that 54 people were killed. The television channel Globovision reported at least 50 killed and about 90 injured. Both cited Ruy Medina, the director of Central Hospital in the city.