Conditions at a prison in Brazil where 57 inmates were killed in fighting on Monday have been described as "terrible" in an official report.
The National Justice Council said that Altamira jail in north-eastern Pará state contained more than double the number of inmates it was built for.
It also said that there were not enough guards to guarantee inmates' safety.
Deadly fights are not uncommon in Brazil, which has the world's third-largest prison population.
The violence broke out at 07:00 local time (10:00 GMT) on Monday when members of a criminal gang housed in Block A of the jail, invaded an annex where members of a rival gang were locked up.
Sixteen inmates were decapitated in the fight which followed. Many more died from smoke asphyxiation after the fighting prisoners set a cell on fire.
Video taken from outside the prison showed smoke billowing from the building and inmates walking around on rooftops.
The inmates also took two prison officers hostage but released them after negotiations with civil and military police.
The fighting lasted for about five hours.
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What did the report say?
The report published by the National Justice Council on Monday – the day the deadly fight occurred – was damning, describing conditions at Altamira as "terrible".
It said that the prison, which has a capacity of 163, held 343 male inmates.
It also pointed out that Altamira had only 33 guards, too low to guarantee safety inside the prison, and called for their number to be increased.
The report concluded that there was "an urgent need for a new prison unit" as Altamira prison was old and had to rely on containers to house the inmates.
Brazilian media say that a new prison which was started to be built in 2013 and meant to be completed in 2016 still has not been finished, putting additional strain on Altamira.
After Monday's deadly incident, prison officials in Pará said the new jail, which will be able to house 600 people, would be finished by the end of 2019.
Which gangs are involved?
Pará state officials said that the inmates who started the deadly fight belonged to a criminal gang known as Comando Classe A (CCA), which they say is one of the more than a dozen gangs affiliated with First Capital Command (PCC), believed to be Brazil's largest and most powerful drug gang.
Their target were members of the Comando Vermelho (Red Command).
The Rio de Janeiro-based Comando Vermelho and the São Paulo-based PCC have been at war since 2016 when they ended an uneasy working relationship after the PCC moved to infiltrate drug smuggling routes controlled by Comando Vermelho.
The feud has spread to prisons across the country where members of the rival gangs are held.
What has the reaction been?
The justice ministry said that ringleaders of the violence would be transferred to more secure units in federal jails. It said 46 of those who took partRead More – Source