WASHINGTON (AP) -- A retired general who commanded "enemy" forces in a recently concluded $250 million U.S. war game says the exercise was rigged so that it appeared to validate new war-fighting concepts it was supposed to test.

Paul Van Riper, who headed the Marine Corps Combat Development Command when he retired in 1997 as a three-star general, said he became so frustrated with undue constraints on his command of "enemy" forces that he quit the role midway through Millennium Challenge 2002, which ended August 15.

His complaints were reported Friday by the Army Times, a private newspaper that covers Army issues. The Times obtained a copy of an e-mail Van Riper sent to colleagues explaining why he had quit.