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.

U.S. Army soldiers participate in a joint river-crossing exercise between South Korea and the United States as a part of the Freedom Shield military exercise in Yeoncheon, South Korea, Thursday, March 20,