On 9 August 1945, the Kwantung Army's commander General Otozō Yamada told Puyi that the Soviet Union had declared war on Japan and the Red Army had entered Manchukuo. Yamada was assuring Puyi that the Kwantung Army would easily defeat the Red Army when the air raid sirens sounded and the Red Air Force began a bombing raid, forcing all to hide in the basement. While Puyi prayed to the Buddha, Yamada fell silent as the bombs fell, destroying a Japanese barracks next to the Salt Tax Palace. In the Manchurian Strategic Offensive Operation, 1,577,725 Soviet and Mongol troops stormed into Manchuria in a combined arms offensive with tanks, artillery, cavalry, aircraft and infantry working closely together that overwhelmed the Kwantung Army, who had not expected a Soviet invasion until 1946 and were short of both tanks and anti-tank guns.