The Pentagon says the US and South Korea will begin a 10-day-long annual military exercise from Monday. US Department of Defence said the Ulchi Freedom Guardian drill is a computer simulated defensive exercise designed to enhance readiness and maintain stability on the Korean peninsula.<br/><br/>It said in addition to South Korea and US forces, UN Command forces from seven states will participate in the exercise. The Ulchi Freedom Guardian drills will be the first joint military exercise between the allies since North Korea successfully flight-tested two intercontinental ballistic missiles in July and threatened to bracket Guam with intermediate range ballistic missile fire in August.