The units of the 1st Area Army proved to be no match for the Red Army when the Soviet Union invaded Manchukuo at the end of World War II. Without adequate armor, ammunition or leadership, many units broke and fled, or surrendered en masse. Many surviving soldiers of the 1st Area Army, including its commanding officer General Seiichi Kita, became prisoners in Siberia and other parts of the Soviet Union after the surrender of Japan on August 15, 1945.