The Cantel prison – located in Quetzaltenango, 205km west of Guatemala City – has inmates from both the Mara Salvatrucha gang and their sworn enemies, the Barrio 18, as well as members of gangs linked to the drug trade.

“At the moment we know of four dead… The preliminary information that we have is that they were beheaded,” National Police spokesman Jorge Aguilar said.

He said that authorities suspect one of the gangs attacked the other in retaliation for an incident that took place days ago.

Aguilar said that 500 police officers were deployed to Quetzaltenango to take control of the prison.

Guatemala’s feared and violent gangs are known for their extortion rackets, as they force businesspeople and bus operators to pay protection money. Those who refuse to pay up are frequently murdered.

Gangs are responsible for nearly half of the 3,500 violent deaths a year in Guatemala, authorities have said.