Allied intervention in the Russian Civil War Powers to withdraw from North Russia and Siberia in 1920, though Japanese forces occupied parts of Siberia until 1922 and the northern half of Sakhalin until 1925. In 1917, Russia was in a state of political strife, and public support for World War I and the Tsar was dwindling. The country was on the brink of revolution. The February Revolution changed the course of the war; under intense political pressure, the Tsar abdicated and the Russian Provisional Government was formed, led initially by Georgy Lvov and later by Alexander Kerensky. The Provisional Government pledged to continue fighting the Germans on
Soviet repressions of Polish citizens (1939–1946) under "de facto" military occupation for many years to come, controlled by the Soviet Northern Group of Forces, which were stationed in Poland until 1956. Some 25,000 Polish underground fighters, including 300 top Home Army officers, were captured by NKVD units and SMERSH operational groups in the fall of 1944. They suffered mass deportations to the gulags. Between 1944 and 1946, thousands of Polish independence fighters actively opposed the new communist regime, attacking country offices of NKVD, SMERSH and the Polish communist secret service (UB). The events of the late 1940s amounted to a full-scale civil war according to some