Katyn massacre hundreds of thousands of political prisoners NKVD mass civilian deportations to Siberia Baltic states eastern Poland Soviet Union Red Army Soviet Poland political
The Soviet Union was responsible for the Katyn massacre of 22,000 Polish officers, and the imprisonment or execution of hundreds of thousands of political prisoners by the NKVD secret police, along with mass civilian deportations to Siberia, in the Baltic states and eastern Poland annexed by the Red Army.