SAO PAULO, Brazil – Rioting inmates rounded up rivals in a Brazilian jail cell Thursday and torched it, killing 25 prisoners and showing once again how gangs rule the lockups across Latin America’s largest nation.

The prisoners took control of the jail before dawn in the south-central Brazilian state of Minas Gerais and chose to settle scores by locking up members of an opposing gang faction in a cell and setting mattresses ablaze, said police Lt. Andrea Amara Lopes.

Authorities who had been trying to negotiate an end to the prison rebellion sprayed water inside to stop the blaze. A short time later, they found burned bodies littering the smoky cell, the state’s public safety department said in a statement. Autopsies were being conducted to determine whether the victims died from their burns, from smoke inhalation or both.

Brutal prison violence and rebellions are common in Brazil’s overcrowded lockups, where gangs often exert more control than their keepers and manage criminal enterprises on the streets with smuggled cell phones.

Authorities investigating the fire in the small town of Ponte Nova found a gun inside the prison after breaking up the rebellion, and were trying to determine how it got inside, the Estado de Minas newspaper reported on its Web site.

The fire came just three days after President Luiz Inacio Lula da Silva announced that Brazil will invest nearly $3.3 billion for new prisons and social programs over the next five years to reduce prison-based violence that often spills outside.