When the Spanish Civil War broke out in July 1936, the Soviets sent 648 aircraft and 407 tanks to the left-wing Republican faction; these were accompanied by 3,000 Soviet troops and 42,000 members of the International Brigades set up by the Communist International. Stalin took a strong personal involvement in the Spanish situation. Germany and Italy backed the Nationalist faction, which was ultimately victorious in March 1939. With the outbreak of the Second Sino-Japanese War in July 1937, the Soviet Union and China signed a non-aggression pact the following August. Stalin aided the Chinese as the KMT and the Communists had suspended their civil war and formed the desired United Front.