Through the 1930s, Japan's military needed imported oil for airplanes and warships. It was dependent at 90% on imports, 80% of it coming from the United States. Furthermore, the vast majority of this oil import was oriented towards the navy and the military. America opposed Tokyo's expansionist policies in China and Indochina and, in 1940–41, decided to stop supplying the oil Japan was using for military expansion against American allies. On July 26, 1940 the U.S. government passed the Export Control Act, cutting oil, iron and steel exports to Japan. This containment policy was seen by Washington as a warning to Japan that any further military expansion would result in further sanctions. However, Tokyo saw it as a blockade to counter Japanese military and economic strength. Accordingly, by the time the United States enforced the Export Act, Japan had stockpiled around 54 million barrels of oil. Washington imposed a full oil embargo imposed on Japan in July 1941.