RIO DE JANEIRO — A second prison riot in a week in the Brazilian Amazon left at least 33 inmates dead on Friday in the northern state of Roraima, the authorities said.
The bloodshed, coming just days after 56 people were killed in a massacre at a prison in the city of Manaus, adds to fears about an intensifying war between drug gangs for control of Brazil’s cocaine trade.
Reflecting the brutal nature of the gang conflict, some of the victims at the Monte Cristo Agricultural Penitentiary in Boa Vista, the capital of Roraima, were decapitated, had their hearts torn out or were dismembered, according to local news reports.
The latest episode is thought to involve fighting between First Capital Command, a gang commonly known by its Portuguese initials, P.C.C., which has roots in the prisons of São Paulo in southeast Brazil, and supporters of the Red Command, a drug trafficking organization that has long had sway in Rio de Janeiro.
The gangs, which operate inside prisons as well as on the streets of many Brazilian cities, are battling for supremacy over the trade in cocaine smuggled into Brazil across the porous Amazonian frontier from countries including Bolivia, Colombia and Peru.
Family of the North, an increasingly influential gang in the Amazon that has allied itself with the Red Command, was responsible for the attack at the prison in Manaus, massacring dozens of rivals from the P.C.C. gang in violence that stunned Brazil. The attack had been planned for months, according to text messages intercepted by intelligence agents.
With the overall death toll in the riots this week approaching 90, the mayhem in Brazil’s prison system is emerging as a simmering crisis for the administration of President Michel Temer, who was already grappling with graft scandals and with growing anger over austerity measures.
Mr. Temer has been chided for what some call a tone-deaf response to the crisis. He said nothing for two days about the killings in Manaus, before calling them a “dreadful accident” and seeking to deflect blame from public agencies because a private contractor runs the prison there.
Although the Manaus riot has fueled a debate over whether management of some prisons should be handed to private companies, the violence in Roraima casts scrutiny directly on state officials. The prison in Boa Vista has a long history of deadly riots and of inmate escapes.
The Boa Vista prison was built for 700 inmates but currently holds about 1,400. Carlos Paixão de Oliveira, a prosecutor in Roraima, publicly criticized the management of the facility in October, when inmates from the P.C.C. gang killed at least 10 rivals from the Red Command.
Mr. Oliveira suggested at the time that the prison should be demolished and replaced.
“If they want, the inmates will carry out a new slaughter in there, because no one has control of that prison,” he said.