Before the attack on Pearl Harbor on December 7, 1941, the US was not at war with Japan, but President Roosevelt was determined to help China. He approved recruiting 100 pilots and 200 support troops to volunteer in China under one-year contracts. After Japan’s attack, the US declared war, and for eight months, the American Volunteer Group (AVG) was the only US fighting force in China. Using P-40s and Chennault's training, they achieved key victories against larger Japanese forces. The AVG was disbanded on July 4, 1942, and became known as the "Flying Tigers."