WASHINGTON (Reuters) - The United States and South Korea will start a joint exercise called Ulchi Freedom Guardian (UFG) on Aug. 21 lasting through Aug. 31, the Pentagon said on Friday, as tensions had escalated over North Korea’s missile and nuclear weapons program.

The statement said about 17,500 U.S. service members would join in the exercise in addition to troops from Australia, Canada, Columbia, Denmark, New Zealand, the Netherlands and Britain.

“UFG is computer simulated defensive exercise designed to enhance readiness, protect the region and maintain stability on the Korean peninsula,” the statement said.

(Corrects paragraph 2 spelling to Colombia)