The Guatemalan authorities say the death toll in a prison fight which began on Sunday has risen to 17.
The Deputy Interior Minister, Elmer Sosa said order had now been restored at the prison in the town of Escuintla, about 60km (37 miles) south of the capital, Guatemala City.
A prison spokesman said a fight had apparently broken out between rival gangs on Sunday night.
The jail is notorious for overcrowding and violence.
“All the dead are prisoners, we have ruled out any guards among the dead,” said Rudy Esquivel, a spokesman for the prison system.
“We are still investigating the cause of the clash.”
More than 3,000 prisoners are held at the jail, which was built to house just 600.
Special forces and the army were sent into the prison to take control and at one point, about 2,300 inmates were engaged in a stand-off with the security forces.
Elmer Sosa, the Deputy Interior Minister, confirmed that some of the inmates had guns.
Mr Sosa said that there were conflicting theories as to what had triggered the violence.
He said there were reports that convicted gang members had clashed with inmates without any gang affiliation after visiting hours on Sunday.