The guerrilla war in the Baltic states was an insurgency waged by Baltic partisans against the Soviet Union from 1944 to 1956. Known alternatively as the "Forest Brothers", the "Brothers of the Wood" and the "Forest Friars", these partisans fought against invading Soviet forces during their occupation of the Baltic states during and after World War II. Similar insurgent groups resisted Soviet occupations in Bulgaria, Poland, Romania and Ukraine.