The South Korean and US militaries on Monday kicked off their biggest-ever combined air force exercise, involving two dozen US stealth fighters, in a show of force against North Korea’s escalating nuclear and missile threats.

The two countries’ air forces launched their annual Vigilant Ace 18 drill, which involves six F-22 Raptors, six F-35A and 12 F-35B stealth fighter jets, according to the South Korean and US air forces. A total of 12,000 US personnel from the air force, marines and navy will also join the exercise. The drill will continue until Dec. 8.

Some 260 aircraft from South Korea and the US are expected to participate in the exercise, military sources here said, while the US Air Force said the drill will involve about 230 aircraft. Seoul’s Defense Ministry declined to reveal the specific number of participating aircrafts.

“This realistic air combat exercise is designed to enhance interoperability between US and Republic of Korea forces and increase the combat effectiveness of both nations,” the US 7th Air Force said in a statement on Monday.

The 7th Air Force highlighted the drill was “not in response to any incident or provocation,” but the exercise is largely seen as US extended deterrence against North Korea, which fired a new Hwasong-15 Intercontinental ballistic missile last Wednesday.

Including two dozen stealth aircrafts, the US also dispatched six EA-18G Growler -- electronic warfare aircrafts -- and B-1B Lacer bombers. A group of F-15C and F-16 jet fighters also joined the drill. Most of them flew from US Air Force bases in Japan.

For the South Korean part, F-15K, KF-16, FA-50 and F-5 jet fighters will participate in the drill. E-737 Peace Eye surveillance aircrafts and KA-1 training fighters will also join the US advanced assets to conduct “realistic” combat training, according to the South Korean Air Force.

“It is quite rare for the US to deploy stealth fighters in such a scale,” said a South Korean military official, who declined to reveal his identity due to the sensitivity of the issue.

During the five-day exercise, the stealth fighters are expected to involve drills targeting North Korea’s mobile missile launchers -- also known as Transporter Erector Launchers -- and underground nuclear and missile facilities.

South Korea’s Defense Ministry told lawmakers Friday that the exercise will apply combined Prepositioned Air Tasking Order (Pre ATO), a classified military plan that lists air sorties for a fixed 24-hour period, with individual aircraft types, and mission types.

The wargame will also focus on conducting precision strikes against North Korea’s long-range artillery units positioned across the border and interdicting operation designed to block North Korea’s Special Forces’ naval infiltration, the military sources said.

“Through real-time coordination and control between the combined forces’ assets, we will ensure our capability to accomplish missions, familiarize with procedures for combined operations and enhance our logistic capability,” the South Korean Air Force said in a statement.

Including the units under the US Pacific Command, two US fighter wings stationed in South Korea -- 8th Fighter Wing and 51 Fighter Wing -- joined the exercise. For South Korea, a total of 10 Air Force units participated in the drill, including 11th, 19th and 20th Fighter Wings.

Meanwhile, one F-22 fighter was caught showing signs of malfunction when it landed on an airbase in southern city of Gwangju after conducting an air combat drill earlier in the day, according to Yonhap News Agency.

The aircraft appeared to stand still on the airstrip for a while after carrying out a 90-minute drill with another three F-22 fighters. Afterwards, the aircraft was drawn by a vehicle to a hanger, while the other three F-22 moved to the place by themselves.

“As Far as we know, all F-22 landed (at the airbase) successfully after completing their mission,” said an official from the South Korean Air Force. “Further confirmation is needed to figure out why the F-22 failed to move by itself.”

(jasonyeo@heraldcorp.com)