South Korea and the United States will conduct major joint military drills starting on August 18.

Axar.az informs, citing Reuters, their military officials said this on Thursday, announcing an annual defensive exercise that has been a source of tension with North Korea.

The 11-day annual exercise, called Ulchi Freedom Shield, will be adjusted this year by rescheduling 20 out of 40 training events to September, South Korea’s Joint Chiefs of Staff spokesperson Lee Sung-jun said at a briefing on Thursday.

The decision to spread out the scheduling included reasons such as extreme weather, he said, denying there were any political factors behind the move.

This year’s drill will test upgraded responses to heightened North Korean nuclear threats as well as cutting-edge technologies used in modern warfare, Lee said, citing conflicts in Ukraine and the Middle East.

The exercise will include a scenario involving a North Korean missile launch, but would not cover a potential nuclear test by Pyongyang, he added.