However, Japan had stationed 150,000 troops on Thai soil, and as the war dragged on, the Japanese increasingly treated Thailand as a conquered country rather than an ally. Although the United States had not officially declared war, on 26 December 1942, US Tenth Army Air Force bombers based in India launched the first major bombing raid, which damaged targets in Bangkok and elsewhere and caused several thousand casualties. Public opinion, and even more importantly the sympathies of the civilian political elite, moved perceptibly against Phibun's alliance with Japan.