PHOENIX – A U.S. Border Patrol agent was killed and another wounded in a shooting early Tuesday in Arizona near the U.S.-Mexico line, according to the Border Patrol.

The agents were shot while patrolling on horseback in Naco, Ariz., at about 1:50 a.m. MST Tuesday, the Border Patrol said in a statement.

The agents who were shot were on patrol with a third agent, who was not harmed, according to George McCubbin, president of the National Border Patrol Council, a union representing about 17,000 border patrol agents.