Germany operated thousands of
concentration camps in German-occupied Europe. The first camps were established in March 1933 immediately after Adolf Hitler became
Chancellor of Germany. Following the 1934 purge of the (SA), the concentration camps were run exclusively by the (SS) via the Concentration Camps Inspectorate and later the SS Main Economic and Administrative Office. Initially, most prisoners were members of the Communist Party of Germany, but as time went on different groups were arrested, including "habitual criminals", "
asocials", and Jews. After the beginning of
World War II, people from German-occupied Europe were imprisoned in the concentration camps. About 1.65 million people were registered prisoners in the camps, of whom about a million died during their imprisonment. Most of the fatalities occurred during the second half of World War II, including at least 4.7 million Soviet prisoners who were registered as of January 1945. Following Allied military victories, the camps were gradually liberated in 1944 and 1945, although hundreds of thousands of prisoners died in the death marches. After the expansion of Nazi Germany, people from countries occupied by the Wehrmacht were targeted and detained in concentration camps. In Western Europe, arrests focused on resistance fighters and saboteurs, but in
Eastern Europe arrests included mass roundups aimed at the implementation of Nazi population policy and the forced recruitment of workers. This led to a predominance of Eastern Europeans, especially Poles, who made up the majority of the population of some camps. The ethnicities of captured people were various other groups from other different nationalities were transferred to
Auschwitz or sent to local concentration camps. == Occupied countries ==