http://www.cnn.com/2005/WORLD/americas/ ... index.html

GUATEMALA CITY (Reuters) -- Guatemala has tightened border security to stop members of youth gangs streaming in from neighboring countries to join a bitter feud that killed 35 inmates in prison riots last week, police said on Tuesday.

Convicts from the Mara Salvatrucha gang attacked rivals from the Mara 18 group with grenades, guns and machetes in Guatemalan prisons last week, breaking a pact between the rival gangs not to fight each other behind bars.

National police chief Erwin Sperisen told Reuters that gang members might enter from abroad as reinforcements in an escalation of the conflict.

"We have taken measures on the borders with Mexico, El Salvador and Honduras to prevent groups of gang members from entering the country," he said.

Central America is home to tens of thousands of youths from the two street gangs and they are frequently in touch with each other across borders.

Regional governments have struggled in recent years to contain a wave of killings and rapes by the gangs, known as "maras," which have their roots in Hispanic gangs in Los Angeles, California.

Sperisen said Guatemalan border posts have been put on alert for large groups of suspected mara members, some easily identified by distinctive tattoos on their faces.

He was particularly concerned about possible infiltration across the frontier with El Salvador, where the Mara Salvatrucha gang is strong.

Two prison guards are under investigation for helping the Mara Salvatrucha stage last week's coordinated jail attacks, Sperisen said.