On 8 July, a special FEAF Bomber Command was set up under the command of Major General Emmett O'Donnell. Although President Truman wasn't willing to risk extensive use of the U.S. bomber force in the United States, which was being used as a deterrent for possible Soviet aggression in Europe, a few groups of B-29 bombers – that were not part of the nuclear strike force – were released. On 13 July, the FEAF Bomber Command took over command of the Twentieth Air Force 19th Bombardment Group and of the Fifteenth Air Force's 22nd and 92nd Bombardment Groups which had been transferred from SAC bases in the United States. Later in July, the Fifteenth Air Force 98th and 307th Bombardment Groups were sent to Japan to join the FEAF. The 92nd and 98th BGs and the 31st SRG operated from bases in Japan, whereas the 19th, 22nd, and 307th BGs were based in Okinawa.