South Korea and the United States on Wednesaday conducted a joint military drill at the Mugeonri defence training field, north of Seoul. The four-day exercise mark the first one commanded by the South Korean military, which is scheduled to retake its wartime operational control, currently held by the United States in 2015 . More than 800 troops from South Korea's tank battalion and two U.S. squadrons engaged in mobile training. Seoul's wartime operational control was given to the U.S.-led United Nations Command at the outbreak of the 1950-53 Korean War, which was later transferred to the South Korea-U.S. Combined Forces Command .Some 28,500 U.S. troops have been stationed here following the war.