Twenty-seven inmates were killed and almost all were decapitated in a Brazilian prison riot.
The riot, that broke out on Saturday, adds to chaos in a penitentiary system in which some 140 inmates have died in gang warfare since the start of the year.
Members of a drug gang started the clash by invading a pavilion in the Alcacuz prison that housed rivals, officials with Rio Grande do Norte state said in a Sunday news conference in the city of Natal.
Police surrounded the prison overnight, but waited until noon to enter because of reports that inmates remained armed and out of their cells.
As with other prison riots across the country earlier this month, almost all the inmates killed were decapitated, with some bodies being partially burned, a person with knowledge of the situation told Reuters.
Behind the bloodshed in some of the nation's prisons is an escalating feud between some of Brazil's most powerful drug gangs, which ended two decades of an uneasy working relationship about six months ago.
Brazil's deadliest jail uprisings in decades have exposed growing turf wars between Sao Paulo-based gang Primeiro Comando da Capital, or PCC, and the Rio de Janeiro-based Comando Vermelho that risk plunging a chaotic penitentiary system deeper into violence.
Their split, which is thought to have happened last year, has unleashed a war with state prisons as their epicentre. The Rio gang has teamed up with five fellow groups around Brazil to counter the PCC's growing might.
