Inmates from rival gangs battled at a prison in Brazil's Goias state on Monday, leaving nine dead and 14 injured, authorities said.
Officials told the Brazilian news site G1 that the violence at the Colonia Agroindustrial prison in the Aparecida de Goiania Complex apparently erupted when inmates from one cellblock invaded three others where prisoners from rival gangs are housed.
The attackers set mattresses on fire when they entered the neighbouring corridors and burned the bodies of those who were killed, authorities said. Firefighters were able to contain the fire.
Authorities confirmed the number of dead, but said identifications had not yet been made, G1 reported.
Local media said about 106 inmates escaped during the riot, and officials had recaptured 29. The reports said 127 other inmates fled during the violence but returned voluntarily.
Officers from the Special Penitentiary Operations Group regained control of the prison with the support of military police about two hours after the riot started.
Exactly one year ago, a prison riot at the Anisio Jobim Penitentiary Complex in Amazonas state caused 56 deaths.
A day later, four prisoners were killed at the Puraqueuqara Prison Unit in the same state.