A prison riot started by rival drug gangs has killed 56 people in one of the bloodiest violence in more than twenty years in the city of Manaus.

Security Chief, Sergio Fontes, mentioned that several decapitated bodies were thrown over the wall of the prison. Most of those killed were from Sao Paulo’s First Capital Command (PCC) drug gang. This massacre is being considered a “revenge killing” in the feud between gangs in Brazil.

The riot began late Sunday in one section of the Anisio Jobim prison facility while in the second section, many prisoners began a mass escape in what authorities said was a coordinated effort to distract the guards.

The problem with overcrowding in prisons is too common in Brazil.  Human rights groups have called the living condition within the prison “medieval” where food is of short supply and the cells are so packed that prisoners have no space to lie down. Currently there are 2,230 inmates in the Anisio Jobim prison that only has a capacity for 590 prisoners.

“These massacres occur almost daily in Brazil,” said Father Valdir Silveria, director of Pastoral Carceraria, a Catholic center that monitors prison conditions in Brazil. “Our prisons were built to annihilate, torture and kill.” Out of 184 inmates that escaped, 40 of them were recaptured.

There had been a truce for many years between the two top drug gangs in the country until it was broken last year.  The PCC and Rio de Janiero’s Red Command drug gang (CV) exchanged gunfire with police and held 12 prison guards as well as 74 prisoners hostage this past weekend in Manaus.

This riot was the deadliest since the 1992 rebellion at the Carandiru prison in Sao Paulo. Police retaking the jail killed One Hundred and eleven inmates.  Director of the Human Rights Watch for Brazil, Maria Canineu said that this most recent violence was the result of “ no government in 20 years giving much attention to the penitentiary system.”

President Michel Temer announced last week the Brazilian government would furnish states with 1.2 billion reais ($366 million) to improve the security and infrastructure in existing prisons and also build new ones.