A U.S. Air Force F-22 Raptor takes off from a South Korean air base in Gwangju, South Korea, Monday, Dec. 4. (Photo: AP)

Hundreds of aircrafts including two dozen stealth jets began training Monday as the United States and South Korea launched their biggest-ever combined air force exercise. The war games come a week after North Korea test-fired its most powerful missile ever, an ICBM that may be able to target the eastern seaboard of the United States.

The five-day drill, which is called Vigilant Ace, is meant to improve the allies' wartime capabilities and preparedness, South Korea's defense ministry said.

The U.S. Seventh Air Force sent major strategic military assets that include six F-22 and 18 F-35 stealth fighter jets for the annual training exercise in the Korean Peninsula. About 12,000 U.S. military personnel are participating. In total, 230 aircraft will be flying at eight U.S. and South Korean military installations in the South.

Some local media report that B-1B bombers will also join aerial drills, but officials did not confirm their participation.

The training, held each year in late fall, is not in response to any incident or provocation, the Seventh Air Force said in a statement.

North Korea's state media said the drill pushes the Korean Peninsula "to the brink of nuclear war."