As a prison in Brazil fell into chaos during a bloody gang riot Monday that left at least 57 dead – including 16 found decapitated – several inmates reportedly celebrated by kicking the severed heads of victims.

Reuters reported that videos had begun to circulate online appearing to show inmates at the Altamira prison in northern Brazil kick severed heads across a floor. Reuters said they couldn’t independently verify the online footage.

BRAZIL PRISON RIOT LEAVES AT LEAST 57 DEAD -- INCLUDING 16 DECAPITATED

In one video posted to a Twitter account called Para News, which says it reports events in the state of Para, where the Altamira prison is located, several inmates can be seen standing on a rooftop in a haze of smoke. One man appears to kick a round object on the ground.

Para state prison authorities said the nearly 5-hour clash began when leaders of a local criminal group known as Comando Classe A set fire to a cell where members of a rival gang, the Comando Vermelho, were located at 7 a.m. local time.

The fire spread rapidly and prevented police forces from accessing the building for several hours, state prisons chief Jarbas Vasconcelos said at a news conference Monday.

BRAZIL INVESTIGATES DEATH OF INDIGENOUS LEADER AFTER MINERS REPORTEDLY ATTACK VILLAGE

No members of the prison's staff were injured. Two prison officials were taken hostage during the chaotic fighting but were eventually released.

"It was a targeted attack. The aim was to show that it was a settling of accounts between the two groups, not a protest or rebellion against the prison system," Vasconcelos said.

NEARLY 60 INMATES KILLED ACROSS FOUR BRAZIL PRISONS OVER TWO DAYS OF VIOLENCE

Many of Brazil’s prisons face the problems of overcrowding and violence. A local judge in charge of the Altamira facility described the overall state of the prison as "terrible."

The Associated Press obtained a July 2019 report from the National Justice Council that it says was filed by the judge in charge, showing that the prison had 343 detainees for a maximum capacity of 163.

Yet Vasconcelos said the situation did not meet the official requirements to be considered overcrowded. "It is not a unit that has a prison overcrowding, we consider overcrowding when it exceeds 210%," Vasconcelos said during the press conference.

CLICK HERE FOR THE FOX NEWS APP

The riot follows the deaths of nearly 60 inmates in May across four different prisons in the state of Amazonas.

In early 2017, more than 120 inmates died in prisons across several northern states when rival gangs clashed over control of drug-trafficking routes in the region. The violence lasted several weeks, spreading to various states.

The Associated Press contributed to this report.