North Korea called the ongoing South Korean-US military drills a plot to invade the country, as it threatened Tuesday to take unspecified "responsible" military steps in response. The North's warning came a day after the South Korean and U.S. forces kicked off their annual computer-simulated command post training and a variety of field exercises for an 11-day run. This year's drills were to involve 48 field exercises, twice the number conducted last year.

In a statement carried by state media, the North's Defense Ministry said it "strongly denounces the reckless military drills of the US and (South Korea) for getting more undisguised in their military threat to a sovereign state and attempt for invading it." An unidentified ministry spokesperson said North Korea's military will "continue to watch the adventurist acts of the enemies and conduct responsible military activities to strongly control the unstable security environment on the Korean Peninsula."