New Delhi, Aug. 19 -- North Korean leader Kim Jong Un condemned South Korean-U.S. military drills and vowed a rapid expansion of his nuclear forces to counter rivals, state media said Tuesday, as he inspected his most advanced warship being fitted with nuclear-capable systems.

Kim's visit to the western port of Nampo on Monday came as the South Korean and U.S. militaries kicked off their annual large-scale summertime exercise to bolster readiness against growing North Korean threats. The 11-day Ulchi Freedom Shield, which the allies describe as defensive, will mobilize 21,000 troops, including 18,000 South Koreans, for computer-simulated command post operations and field training.

North Korea has long denounced the allies' joint drills ...