Brazilian authorities said Friday that at least 33 prisoners have died in a penitentiary in the northern state of Roraima, adding to 60 deaths reported at other prisons.
Friday's statement from the justice secretary said the prisoners died overnight at the Agricultural Penitentiary of Monte Cristo. It did not provide details.
A police statement said officers, including a heavily armed military-like riot squad, had been deployed to the prison. A military police spokesman declined to comment further.
The apparent bloodshed comes just days after rebellions in other two prisons left 60 dead in the neighboring state of Amazonas.
Authorities say gangs are fighting for the control of drug routes in the northern part of the country, which borders Colombia, Venezuela, Peru and the Guianas.
Four prisons in the neighboring state of Amazonas saw riots Sunday and Monday. One institution suffered the country's worst prison bloodshed since 1992, with half of the 56 slain beheaded and several others also dismembered. In another of the riots, four prisoners died.
A total of 184 inmates escaped from Amazonas prisons in the disturbances. As of Thursday afternoon, only 65 had been recaptured.
Authorities say that in Amazonas, the local Family of the North gang attacked members of Sao Paulo-based First Command, Brazil's biggest criminal organization. The two fight over the control of prisons and drug routes in northern Brazil.
In October, a riot at the Agricultural Penitentiary of Monte Cristo, the same where disturbances were reported on Friday, left 18 dead.