the Korean held Winter Olympics. South Korea asked the International Olympic Committee (IOC) to ban the Japanese Rising Sun Flag from the 2020 Summer Olympics in Tokyo, and the IOC said in a statement "sports stadiums should be free of any political demonstration. When concerns arise at games time we look at them on a case-by-case basis." European Union The European Union (EU) and South Korea are important trading partners, having negotiated a free trade agreement for many years since South Korea was designated as a priority FTA partner in 2006. The free trade agreement was approved in September 2010, and took effect on 1 July 2011. South Korea is the EU's tenth largest trade partner, and the EU has become South Korea's fourth largest export destination. EU trade with South Korea exceeded €90 billion in 2015 and has enjoyed an annual average growth rate of 9.8% between 2003 and 2013. The EU has been the single largest foreign investor in South Korea since 1962, and accounted for almost 45% of all FDI inflows into Korea in 2006. Nevertheless, EU companies have significant problems accessing and operating in the South Korean market because of stringent standards and testing requirements for products and services often creating barriers to trade. Both in its regular bilateral contacts with South Korea and through its FTA with Korea, the EU is seeking to improve this situation. United States The close relationship began directly after World War II, when the United States temporarily administrated Korea for three years (mainly in the South, with the Soviet Union engaged in North Korea) after Japan. Upon the onset of the Korean War in 1950, U.S. forces were sent to defend against an invasion from North Korea of the South, and subsequently fought as the largest contributor of UN troops. The United States participation was critical for preventing the near defeat of the Republic of Korea by northern forces, as well as fighting back for the territory gains that define the South Korean nation today. Following the Armistice, South Korea and the U.S. agreed to a "Mutual Defense Treaty", under which an attack on either party in the Pacific area would summon a response from both. In 1967, South Korea obliged the mutual defense treaty, by sending a large combat troop contingent to support the United States in the Vietnam War. The US has over 23,000 troops stationed in South