Japanese air attacks on the Mariana Islands and anti-aircraft guns shot down about 37 Japanese aircraft during these raids. After the Marianas began to come under attack, the United States military stepped up its raids on the Japanese-held islands which could be used to launch raids on the B-29 bases. Particular attention was given to Iwo Jima, as it was correctly assumed that the Japanese aircraft which attacked the Marianas were flying from Japan and staging through the island en route to their targets. Following the first raid against Saipan in November, XXI Bomber Command B-29s were dispatched against Iwo Jima's airfields on November 5 and 8.
Internment of Japanese Americans (including the President Franklin D. Roosevelt and FBI Director J. Edgar Hoover) dismissed all rumors of Japanese-American espionage on behalf of the Japanese War effort, pressure mounted upon the Administration as the tide of public opinion turned against Japanese Americans. Civilian and military officials had serious concerns about the loyalty of the ethnic Japanese after the Niihau Incident which immediately followed the attack on Pearl Harbor, when a civilian Japanese national and two Hawaiian-born ethnic Japanese on the island of Ni'ihau violently freed a downed and captured Japanese naval airman, attacking their fellow Ni'ihau islanders in the process. Several concerns