Finnish Operation of the NKVD
The Finnish Operation of the NKVD was a mass arrest, execution and deportations of persons of Finnish origin in the Soviet Union by the NKVD during the period of the Great Purge (1937–1938). It was a part of the larger mass operations of the NKVD which targeted many minority nationalities in the Soviet Union.
Source: Wikipedia — Finnish Operation of the NKVD (CC BY-SA 4.0)