At least five inmates have burned to death in a fire at a prison in north-eastern Brazil, officials say, BBC reported.
They said about 40 other prisoners were injured at the jail in the coastal town of Joao Pessoa.
It was not immediately known how the fire started, but some reports suggest it followed a riot over attempts to transfer an inmate to another jail.
Brazil's prisons are notoriously overcrowded and are often run by organised gangs.
"There was a prisoners' rebellion protesting against the transfer to a high security prison of one of the inmates," a military police spokesman was quoted as saying by the AFP news agency.
The spokesman said that the rioters then "set fire to the place".
Firefighters and police had to break down walls to reach trapped prisoners, reports say.