As American forces pushed their campaign on Okinawa and tightened their naval encirclement of the Japanese islands in mid-1945, the divergence between British and American policies toward Thailand, the rivalry between SOE Force 136 and OSS Detachment 404, and the British focus on the recapture of their lost colonies complicated efforts to supply, train, and control substantial guerrilla forces in Thailand. Meanwhile, Japanese forces in Thailand showed an increased awareness of underground activities, raising fears of a Japanese military strike against the Thai.

Security concerns were never far from the mind of Richard Greenlee as he operated for a month, from late April 1945, as the sole American officer in Bangkok, a city swarming with Japanese troops. The loss of electrical power at Maliwan Palace since the bombing raid of 14 April meant that his radiomen had to use a noisy gas-powered generator for up to eight hours a day to meet their schedules. When the operators sought to solve the noise problem by fitting a car muffler to the generator, it overheated and froze up. Fortunately, Greenlee managed to appropriate a replacement from the supplies of a recently infiltrated agent, but the noise problem remained unsolved.

Concern that the Japanese were aware of enemy agent and supply landings near Hua Hin proved unsettling, too, and led Pridi on 15 May to request a halt to flights to the Gulf of Thailand.