(CNN) -- A prison brawl and fire left 29 inmates dead and dozens injured in eastern Bolivia, state media reported Friday.
The incident at Palmasola prison in Santa Cruz started with a battle between two groups.
A child was among the fatalities, state-run ABI news agency said. At least 50 people were injured.
Bolivia allows children to legally live with incarcerated parents.
President Evo Morales expressed sympathy and solidarity with victims and their families. He demanded an investigation into the incident, which authorities described as the deadliest prison violence in Bolivia.
State media reported that the fire started early Friday with a confrontation between two groups of inmates. One group attacked the other with sharp weapons and firearms, and set two liquid gas cylinders on fire, sparking an explosion.
At least 100 additional troops were dispatched to reinforce security inside the prison, according to state media.
The prison is a maximum security facility.