At least 25 inmates have died in clashes between two rival factions in a prison in far northern Brazil, according to local news media citing police.
Seven of the dead were beheaded and six burned to death in Sunday's violence in a prison in Boa Vista, the capital of Roraima state, the news site G1 reported, citing local police.
The bloodshed began when inmates of one wing of the Agricola de Monte Cristo prison broke into another wing.
Inmates were armed with knives and wooden clubs, an inmate's wife who was in the prison when the riot broke out told G1.
Uziel Castro, Roraima's secretary of justice, said that the fight erupted during visiting hours, and some 100 relatives of inmates were briefly held hostage.
The rioters demanded that a judge come to hear their demands.
Instead, Special Operations Police stormed the prison, released the hostages and regained control of the site by sundown.
"All the hostages were released," Castro said, adding that most of them were women.
The prison, about 3,400km northwest of Rio de Janeiro, is in a state that borders Venezuela.
Fights and riots are common throughout Brazil's overcrowded prison system. It has the fourth largest prison population behind the US, China and Russia.
Police and state officials did not immediately respond to phone calls for comment.
Source: Agence France Presse