In 1941 the Soviet Union’s fortified borders were manned by units of the NKVD (People’s Commissariat for Internal Affairs). These units were almost entirely destroyed in the first weeks of the campaign. After this, NKVD troops were chiefly used for internal security, but could potentially fight on the frontline as they did at Stalingrad in 1942 and during the Crimean Offensive in 1944.
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