The United States Army Military Government in Korea (USAMGIK; Korean: 재조선 미육군 사령부 군정청; Hanja: 在朝鮮美陸軍司令部軍政廳) was the official ruling body of the southern half of the Korean Peninsula from September 8, 1945 to August 15, 1948. In addition, the U.S. military was largely unprepared for the challenge of administering the country, arriving with no knowledge of the language or political situation. Thus, many of their policies had unintended destabilizing effects. Waves of refugees from North Korea (estimated at 400,000) and returnees from abroad also helped to keep the country in turmoil.