South Korean and the U.S. marine troops conducted air and ground joint combat training on Wednesday near the port city Pohang, about 223 miles south of Seoul.
The drills mobilised about 1,300 Marine Corps from the two countries, as well as eight Korean Assault Amphibious Vehicles (KAAV), armoured combat Earthmover, mine-Clearing Line Charge (MICLIC) and several mortars.
North Korea launched two Musudan intermediate-range missiles on June 22 drawing strong condemnation from South Korea, Japan and the United States for infringing United Nations sanctions designed to stop Pyongyang's nuclear and missile development programmes.
There are 28,500 U.S. troops stationed in the South as part of combined defence with the South's military of more than 600,000. The North has an army of 1.2 million.
The two Koreas are in a technical state of war under a truce after the 1950-53 Korean War.