TUCSON, Ariz (Reuters) - A U.S. Border Patrol agent fired a gun while breaking up a drug-smuggling attempt on the Arizona-Mexico border, authorities said on Tuesday, possibly injuring at least one person in Mexico.
The incident occurred on Monday morning close to the border fence in Nogales, Arizona, the Border Patrol's Tucson sector said in a statement.
"A Border Patrol agent fired a service weapon east of Nogales while responding to illegal narcotics activity. Authorities are investigating claims that at least one subject was injured," the statement said.
It added that local, federal and international authorities were investigating the incident in the city, which flanks the namesake city of Nogales, in Mexico's northern Sonora state.
Manuel Johnson, a special agent with the FBI's Phoenix field office, said the incident was being treated as an assault on a federal officer.
Calls to Nogales Police Department seeking further details were not immediately returned on Tuesday.
The Nogales International newspaper cited Nogales Police Chief Jeffrey Kirkham saying he was told the Border Patrol agent fired in self defense after being pelted with rocks.
The newspaper said police in Nogales, Mexico, told a local radio station there that they had interviewed a man being treated for gunshot wounds to the abdomen and left forearm at the city's hospital.
Frustrated by tighter security on the U.S.-Mexico border, illegal immigrants and drug traffickers regularly pelt U.S. agents with rocks and other missiles.
Last January, a U.S. Border Patrol agent in Nogales was involved in a shooting that resulted in the death of a teenage boy trying to cross illegally into Arizona.
(Reporting By Tim Gaynor; Editing by Cynthia Johnston and Greg McCune)