South Korea and the United States today began their annual joint military exercises, but they paused live-fire training. Seoul is investigating how two of its fighter jets mistakenly bombed a civilian area during a warm-up drill last week. The modified Freedom Shield exercise, which combines computer simulations and field training and runs through March 20, drew the condemnation of North Korea. Pyongyang issued a statement calling the drill a dangerous provocative act that increases the risks of military conflict. About 30 people were injured, two of them seriously, when two South Korean KF-16 fighter jets mistakenly fired eight MK-82 bombs on a civilian area in Pocheon, a town near the North Korean border. The bombing occurred while South Korean and US forces were engaging in a live-fire drill ahead of the larger Freedom Shield exercise.