Concentration camps were camps where people were imprisoned without due process. Those interned in the camps by the Nazis included Jews, Sinti and Roma (gypsies), homosexuals, communists, political opponents, Jehovah's Witnesses, and prisoners of war. There were transit camps where prisoners were held temporarily pending further deportation, labour camps where prisoners performed forced labour, prisoners of war camps for captured members of the Allied armed forces, and prison camps where the regime was extremely harsh and torture was commonplace. A unique category was the extermination camps, where people were systematically murdered in massive numbers.