SEOUL (REUTERS) - The air forces of the United States and South Korea are scheduled to hold a regular joint drill early next month, deploying six F-22 Raptor stealth fighters in the exercise, a South Korean defense ministry official said on Friday (Nov 24).

The drill called "Vigilant Ace" will be held from Dec 4-8, the official told Reuters.

According to South Korea's Yonhap news agency, it will be the biggest number of F-22 fighter jets to participate in a single drill to date.

The Vigilant Ace drill is a biannual, bilateral training event held by the United States and South Korea regularly to simulate wartime defenses.

In previous exercises, roughly 16,000 US troops have participated in the drill.

The exercise comes as North Korea continues to move forward with the development of its nuclear and missile program in defiance of international condemnation and sanctions, although it has not conducted tests for two months.

Joint drills such as these are protested strongly by Pyongyang, which sees the exercises as an aggression against the isolated state.