For the second time in three years, a squadron of fighter jets used to portray the enemy in training exercises will be reactivated at Nellis Air Force Base, the Air Force chief of staff announced Thursday.

In a letter to Air Force personnel, Gen. T. Michael Moseley said the "legendary" 65th Aggressor Squadron equipped with nine F-15C Eagles will be used to scrimmage against pilots in air combat training exercises at the Nellis range, north of the Las Vegas Valley. Eventually the squadron will be expanded to 24 fighter jets.

The squadron will be reactivated Jan. 12, a base spokesman confirmed.

"The 65th and other aggressor units will provide realistic adversary training in air, space and information operations that make us even better," Moseley, the Air Force chief of staff, said in a statement.

"Their training will keep us innovative as we fight this global war on terror," Moseley stated.

In October 2003, the Air Force reactivated the 64th Aggressor Squadron at Nellis with seven camouflaged F-16 Fighting Falcons. The 64th's roots date back to 1941 when it began as the 64th Pursuit Squadron in World War II.

The 65th Aggressor Squadron was last active in 1989 when its pilots flew F-5E Tiger II aircraft.

From 1972 until 1990, aggressor aircraft chalked up more than 250,000 sorties in more than 1,000 training deployments in the United States and overseas. Faced with budget cuts in 1990, the aggressor squadron was deactivated and reformed as an adversary division for Red Flag training exercises at the Nellis range.

In his announcement Thursday, Moseley told members of the Air Force to use aggressor opportunities "to continually innovate and improve our tactics, technologies and training. If we do that," he said, "then we will continue to dominate air, space and cyberspace for the joint team."