Federal authorities are investigating a shooting Tuesday along the Arizona-Mexico border that left one Border Patrol agent dead and another wounded.

The shooting occurred shortly before 2 a.m., when three agents on horseback were dispatched to an area near Naco after a ground sensor had been activated, said George McCubbin, president of the National Border Patrol Council an association of 17,000 agents and staffers.

McCubbin said one of the agents was killed, another wounded in the ankle and buttocks and third escaped without injury. The wounded agent, McCubbin said, was recovering at a local hospital.The agents were not identified, but McCubbin said they were assigned to the Border Patrol station re-named just two weeks ago in honor of Agent Brian Terry.