NKVD filtration camps
NKVD screening and filtration camps (Russian: проверочно-фильтрационные лагеря НКВД СССР), originally known as NKVD special-purpose camps / NKVD special camps (Russian: лагеря специального назначения НКВД СССР, спецлагеря НКВД), were camps for the screening of the Soviet soldiers returned from enemy occupied territories, enemy imprisonment, or enemy encirclement. There was concern among Soviet leaders that citizens that had been outside the supervision of the government and security services may need screening to ensure their political loyalty.