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.

South Korea and the United States on Monday began a large-scale annual joint military exercise to strengthen their combined defense c

North Korea fired "multiple unidentified ballistic missiles" on Monday, South Korea's military said, the same day Seoul and Washington began a major annual joint military drill known as Freedom Shield.

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.

South Korea's military said that Pyongyang fired multiple ballistic missiles off the west coast, just hours after South Korea and the US kicked off their annual military drills.

North Korea condemned an upcoming U.S.-South Korea joint military exercise Friday, saying that "counteraction is inevitable" and warning that the allies would "pay dearly."

The North Korea Foreign Ministry said U.S.-South Korea joint military exercises are "a dangerous provocative act," state media KCNA reported on Monday. Annual South Korean and U.S. military exercises called Freedom Shield are due to begin on Monday and run until March 20.

North Korea fired several ballistic missiles into the sea after South Korean and U.S. troops began their large annual combined drills, Seoul said.