Three prisoners were beheaded and at least five other people were injured in a riot that erupted on Sunday in a southern Brazilian prison, authorities said.
Inmates of the prison in the city of Cascavel took at least two agents and several other inmates hostage in the uprising, said military police captain Ricardo Pinto. He said negotiations for better conditions in the prison were still under way 12 hours later.
Prisoners set some objects on fire and were using metal poles to cause damage to the 928-bed prison that housed more than 1,000 inmates at the time.
Authorities initially reported that two men were decapitated, but later learned of a third prisoner who was killed the same way. The three men were not identified.
The revolt began before sunrise when a prison guard was captured during breakfast, Pinto said.
Dozens of the prisoners climbed onto the building's rooftop, with their faces covered with white fabric. Local media images showed at least 30 rebellious inmates shouting while they beat men held with ropes around their necks, or whose hands were tied behind them. The rioting inmates waved banners emblazoned with the initials PCC for a criminal prison gang formed in the 1990s.
Jairo Ferreira, a lawyer for the prison guards' union, told local news site CGN that at one point the inmates put the decapitated head of one victim on the lap of a custodian who was initially held hostage and later freed.
Relatives arriving at the prison to visit inmates waited outside as night fell, trying to get information about their loved ones.
Ferreira said the prisoners rioted to demand better food and medical care in the prison.
Pinto said the revolt may also have been related to the recent convictions of two prisoners.