FBI: Mexican soldiers used rifles to chase off U.S. Border Patrol after shooting of teenager

CIUDAD JUAREZ, Mexico (AP) - Pointing their rifles, Mexican security forces chased away U.S. authorities investigating the shooting of a 15-year-old Mexican by a U.S. Border Patrol agent on the banks of the Rio Grande, the FBI and witnesses told The Associated Press on Wednesday.

The killing of the Mexican by U.S. authorities - the second in less than two weeks - has exposed the distrust between the two countries that lies just below the surface, and has enraged Mexicans who see the death of the boy on Mexican soil as an act of murder.

Shortly after the boy was shot, Mexican soldiers arrived at the scene and pointed their guns at the Border Patrol agents across the riverbank while bystanders screamed insults and hurled rocks and firecrackers, FBI spokeswoman Andrea Simmons said. She said the agents were forced to withdraw.

"It pretty quickly got very intense over on the Mexican side," she said, adding that FBI agents showed up later and resumed the investigation, even as Mexican authorities pointed guns at them from across the river.

A relative of the dead boy who had been playing with him told the AP that the Mexicans - who he described as federal police, not soldiers - pointed their guns only when the Americans waded into the mud in an apparent attempt to cross into Mexico.