A U.S. Border Patrol agent has been killed and another wounded in a shooting in the southwestern state of Arizona near the border with Mexico.

The agents were shot early Tuesday while on patrol in the town of Naco, Arizona. Authorities have not yet released their identities.

The Department of Homeland Security says the wounded agent was airlifted to a hospital following the shooting.

It has been nearly two years since the last U.S. Border Patrol agent was fatally shot in the line of duty. That agent was Brian Terry, who was killed in a shootout with Mexican bandits in December 2010.

The killing took place during a controversial operation known as “Fast and Furious,” in which U.S. federal agents allowed guns to be smuggled into Mexico, hoping they would lead them to arms traffickers. But agents lost track of most of the weapons, two of which were used in the murder of Agent Terry.