Four inmates were killed and five others wounded as rival gangs clashed at a Guatemalan youth prison, reports from Guatemala City reaching in Mexcio City said on Thursday.
Among the victims, one was shot dead, two were beaten to death and a fourth died of a bullet wound after being rushed to hospital, police said.
The clash broke out between two rival youth gangs in the prison before police brought the situation under control.
At least 14 gang members were killed in September 2005 when gunmen with assault rifles burst into the prison.
And in early August last year, at least 36 gang members were killed and more than 60 wounded in simultaneous riots in seven Guatemalan prisons.
Battles between the two largest gangs, the Mara Salvatrucha and Mara 18, have become a major concern in Guatemala, El Salvador and Honduras.