After the 1941 Japanese attack on U.S. forces at Pearl Harbor, Hawaii, during World War II, Mexico severed diplomatic relations with the Axis powers, and after German U-boats sank several of its oil tankers in the Gulf of Mexico in May 1942, it declared war on those nations. Following defensive patrols for enemy submarines, Mexico negotiated with the U.S. to train the 201st Fighter Squadron of the Mexican Expeditionary Air Force in Texas, where the unit became known as the Aztec Eagles. The 300 volunteers arrived in Laredo in July 1944, went to Randolph Field in San Antonio, relocated to Foster Field in Victoria in August, trained there and at nearby auxiliary fields, graduated in October 1944, deployed to Pocatello Air Base in Idaho, returned to Majors Field in Greenville because of bad weather, and later reported to Brownsville for final aerial gunnery practice. President Manuel Ávila Camacho pressed for the squadron's deployment to the Pacific, partly because of his admiration for U.S. Gen. Douglas MacArthur and partly because he believed it could help liberate what he called a people with "A continuity of idiom, history and traditions." The squadron reached the Philippines in April 1945 and joined the U.S. 58th Fighter Group of the Fifth Fighter Command, Fifth Air Force. It flew 96 combat missions in successful attacks on Japanese forces and was the only Mexican military unit to see overseas combat during the war, remaining a source of pride for Mexico and the United States.