The dictator, eager to shut out the influence of Hollywood and K-pop, has been exalting a “shock brigade” of 300,000 teens and 20-somethings drafted into flood reconstruction.

South Korea 's Yonhap News Agency said North Korea might be using a vertical cold-launch system to fire the missiles. The system, which is commonly associated with submarine- and ship-based weapons, ejects a missile from its container before the missile ignites midair.

North Korea's foreign ministry vowed the "toughest counteraction" against the United States as long as Washington "refuses" the country's sovereignty.