The sovietisation was interrupted by the German occupation in 1941–1944. The Baltic Offensive re-established the Soviet control in 1944–1945, and resumed sovietisation, mostly completed by 1950. The forced collectivisation of agriculture began in 1947, and was completed after the mass deportation in March 1949. Private farms were confiscated, and farmers were made to join the collective farms. An armed resistance movement of 'forest brothers' was active until the mid-1950s. Hundreds of thousands participated or supported the movement; tens of thousands were killed. The Soviet authorities fighting the forest brothers also suffered hundreds of deaths. Some innocent civilians were killed on both sides. In addition, a number of underground nationalist schoolchildren groups were active. Most of their members were sentenced to long terms of imprisonment. The punitive actions decreased rapidly after Joseph Stalin's death in 1953; from 1956–58, a large part of the deportees and political prisoners were allowed to return.