The riots began when relatives visited the prisoners, after that about 100 visitors were taken hostage.
At least seven people were reportedly beheaded during the riot while bodies of six more victims are said to have been burned.
According to Folha de Boa Vista media outlet, the incident was caused by a conflict between members of two warring drug dealer gangs.
Authorities of the Roraima state sent special police units to the prison and managed to release the hostages.
Prison upheaval in Brazil results in 25 dead, multiple hostages
17 October 2016
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A prison upheaval in a Brazilian city of Boa Vista on Sunday claimed the lives of at least 25 prisoners, according to the police authorities of Roraima state.
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