Alonso Castillo / Reuters file Friends of Ramses Barron hug outside his home while mourning his death in Nogales, Mexico, on Jan. 6, 2011.

PHOENIX - U.S. authorities will not bring charges against a Border Patrol agent in Arizona who shot dead a rock-throwing Mexican teenager two years ago because the fatal injury did not occur in the United States, the Justice Department said on Friday.

An unidentified Border Patrol agent shot Ramses Barron, a 17-year-old Mexican citizen, through the border fence in Nogales, Arizona, in the early hours of January 5, 2011.

The incident began after agents responded to reports of a group of people trying to smuggle suspected drug packages across the border, the department said. The group, among them Barron, then pelted the agents with rocks, forcing them to take cover.

An independent investigation concluded that the agent fired the fatal shot after Barron ignored commands in Spanish to stop throwing rocks. A videotape of the incident captured Barron making a "throwing motion with his right arm, then falling to the ground," the department said in a news release.

No charges were brought because the department "lacks jurisdiction" to prosecute the agent under a criminal civil rights use of force statute that "requires that the victim be in the United States when he was injured," it said.

Over the past five years, U.S. border agents have fired into Mexico at least 10 times, killing six Mexicans, according to a report released earlier this year by the Washington Monthly and the Investigative Fund at The Nation Institute.

In another Border Patrol shooting incident in Nogales in October, 16-year-old Mexican citizen Jose Antonio Elena Rodriguez was shot at least seven times from behind after an agent, or agents, opened fire across the border.

Following the shooting, Mexican authorities condemned the U.S. Border Patrol's use of lethal force and called for a timely and transparent investigation, which is continuing.

In a separate report released on Friday, the Justice Department said it would not pursue charges against another Border Patrol agent who shot and killed a 19-year-old U.S. citizen in the border city of Douglas, Arizona, in March 2011.

Douglas police officers had earlier spotted Carlos LaMadrid loading suspected drug bundles into a truck. LaMadrid then fled south in the truck toward the border, striking a Border Patrol agent's vehicle, before scrambling up a ladder placed against the border fence, the report said.

The unidentified agent opened fire after another man on top of the fence began throwing "brick sized rocks." LaMadrid, who got "in the line of fire" between the agent and the rock thrower, was struck by four bullets and later died in hospital, it said.

In that case, the department said, a careful and thorough review concluded that there was insufficient evidence to pursue homicide or criminal civil rights charges against the agent.