 These were guarded by a garrison of former Czechoslovakian POWs trapped in Siberia by the chaos of World War I and the subsequent Revolution.Omsk became a prime target for the Red Army leadership, which viewed it as a major target of their Siberian campaign and eventually forced Kolchak and his government to abandon the city and retreat along the Trans-Siberian eastward to Irkutsk.Bolshevik forces entered the city in 1919.