At least 25 inmates died in a massive prison fight on Sunday in the northern Brazilian city of Boa Vista, according to local media who were citing police.

Seven of those killed were beheaded and six were burned to death, the news site G1 reported, citing local police.

The fighting broke out between two rival factions when one group broke into another wing of the Agricola de Monte Cristo prison.

Inmates were armed with knives and wooden clubs, a prisoner's wife who was in the prison told G1.

Sunday's riot broke out during visiting hours and around 100 relatives of inmates were briefly taken hostage, said Uziel Castro, the Secretary of Justice for Roraima state where the prison is located.

The prisoners demanded that a judge come hear their demands, but Special Operations Police stormed the prison and regained control of the area by the evening on Sunday.

"All the hostages were released," Castro said, adding that most of them were women.

The prison is located around 3,400 kilometers (2,113 miles) northwest of Rio de Janeiro, in a state that borders Venezuela. Many prisons in Brazil are overcrowded and riots and mass escape attempts are common across Brazil.

rs/rc (AFP, dpa)