The United States military and forces of South Korea have begun large scale air exercisesintended to portray a show of force to the North Koreans.

US aircraft, including F-22s, F-35s, and B-1s, on Monday began a massive exercise alongside South Korean forces, a move North Korean officials say brings the countries to the “brink of nuclear war.”

Exercise Vigilant Ace 18 runs from Monday to Friday, and includes 12,000 US personnel along with airmen with the Republic of Korea Air Force. The “realistic air combat exercise” also includes US Marine Corps and US Navy personnel, with a total of 230 aircraft at eight locations, according to Pacific Air Forces. The aircraft include F-22s, F-35s, F-16s, F-15s, B-1s, F-18s, E/A-18s, and F-4s.