In a bid to keep Washington's ongoing denuclearization talks with North Korea from faltering, U.S. Defense Secretary Jim Mattis said Wednesday that a major joint military exercise with South Korea would be scaled back.

"We have taken a decision," Mattis said, according to a transcript of his conversation with reporters. "We are not canceling exercises. We are realigning one exercise."

Asked if it was the Foal Eagle exercise, a large-scale drill typically held in the spring, Mattis confirmed this was the case.