Threat posed by Pyongyang's growing nuclear arsenal and advancing missile technology will be the focus of the exercise

South Korea and the United States will conduct major joint military drills starting on August 18, officials said, although they will delay parts of the annual exercises that have been a source of tension with North Korea to later in the year.

The Aug. 18-28 exercise may trigger an angry reaction from North Korea, which calls the joint drills invasion rehearsals.