Hundreds of warplanes and several weapons began training as the US and South Korea embarked on a massive aerial drill on Monday, 4 December, in a strong show of force against the reclusive North Korean regime. The joint drill, codenamed Vigilant ACE (air combat exercise), is taking place within days of Pyongyang's launch of a new intercontinental ballistic missile (ICBM), although the exercise was scheduled before the North's provocative act.