Completed the following sentence: In 1937, however, Stalin purged the Red Army of its best military leaders. Fearing that the military posed a threat to his rule, Stalin jailed or executed many Red Army officers, estimated in thousands, including three of five marshals.<unk> Fearing that the military posed a threat to his rule, Stalin jailed or executed many Red Army officers, estimated in thousands, including three of five marshals. <unk> <unk> <unk> <unk>
Soviet<unk>Finnish War (Winter War) of 1939<unk>40 and in World War II.