World opinion was not supportive of the policies of the Japanese government. The League of Nations first report on the conflict issued on October 6, 1937 stated that Japan's response to the situation at the Marco Polo bridge was out of proportion to what actually happened between the soldiers. The report also stated that Japan's aggression towards China could not be justified under any existing legal instruments or under the right of self-defense. The United States agreed with the position of the League of Nations.
From the outset,the interests of third powers in China such as Great Britain and the United States were under attack by the Japanese. Britain was too involved in the war in Europe to confront Japan, so the country that was most responsible for restraining the Japanese was the United States.
On December 12,1937 a Japanese aircraft bombed and sank an Americal ship called the "Panay" in the Yangtze River. Japan claimed that the sinking was an accident and that no further incidents of this kind would happen in the future. After repeated warnings from the United States to the Japanese government to keep the assurances that resulted from the "Panay" sinking, on July 1 1938 the United States placed an embargo on the sale of aircraft and aircraft equipment to Japan.
The Soviet Union was also concerned in what was happening in China. At the outbreak of the Sino-Japanese conflict the Soviet Union gave to the Chinese extensive aid in the form of military supplies,technical advice,as well her troops stationed along the border near Manchuria.
By July 1940, China was recieving aid from the United States,Great Britain and the Soviet Union.