The modified Freedom Shield exercise, which combines computer simulations and field training and runs through March 20, still drew the condemnation of nuclear-armed North Korea.

North Korea launched several ballistic missiles toward the Yellow Sea on Monday afternoon, Seoul's military said, on the first day of a large-scale joint U.S-South Korea military exercise on the Peninsula.

North Korea on Monday condemned joint U.S.-South Korean military drills as a "provocative act," warning of the danger of sparking war with "an accidental single shot," days after Seoul's air force mistakenly bombed a village on its own territory.