According to Soviet sources, German military intelligence discovered, after breaking a U.S. Navy code, that a major conference would be held at Tehran in mid-October 1943.[3] Based on this information, Adolf Hitler approved a scheme to kill all three Allied leaders. Operational control was passed to Ernst Kaltenbrunner, chief of the Reich Security Main Office, who chose Skorzeny to head the mission. The German agent Elyesa Bazna (codenamed "Cicero"), in Ankara, Turkey, was also brought into the operation.