The United States and South Korea went ahead with large-scale joint aerial drills on Monday, a move North Korea had said would push the Korean peninsula to “the brink of nuclear war”, ignoring calls from Russia and China to call them off.

The drills come a week after North Korea said it had tested its most advanced intercontinental ballistic missile capable of reaching the United States as part of a weapons program that it has conducted in defiance of international sanctions and condemnation.

The annual U.S.-South Korean drill, called Vigilant Ace, will run until Friday, with six F-22 Raptor stealth fighters to be deployed among the more than 230 aircraft taking part.

North Korea’s Committee for the Peaceful Reunification of the Country called U.S. President Donald Trump “insane” on Sunday and said the drills would “push the already acute situation on the Korean peninsula to the brink of nuclear war”.

F-35 fighters will also join the drills, which will include the largest number of 5th generation fighters ever to have taken part in.

Around 12,000 U.S. service members, including from the Marines and Navy, will join South Korean troops. Aircraft taking part will be flown from eight U.S. and South Korean military installations.

North Korea has tested dozens of ballistic missiles and conducted its sixth and largest nuclear bomb test in September, in violation of U.N. Security Council resolutions.

It has said its weapons programs are a necessary defense against U.S. plans to invade. The United States, which has 28,500 troops stationed in South Korea, a legacy of the 1950-53 Korean War, denies any such intention.