One of the NKVD "special operations" against representatives of national minorities was the so-called "Latvian". It began with the M. Yezhov ciphered tegram No. 49990 of November 30, 1937, which stated in order to liquidate the work of Latvian intelligence and to defeat the nationalist, anti-Soviet activities of Latvians in the USSR to "carry out arrests of the Latvians suspected of espionage, sabotage, anti-Soviet nationalist work " simultaneously in all republics, territories and regions since December 3, 1937.
The Latvians, who were on operational records, political emigrants from Latvia, arrived in the USSR after 1920, defectors from Latvia, leaders, board members and staff of the Prometheus Society and Latvian clubs local branches, leaders and members of the bureau of local branches of the Latvian Shooters society at the Society for Assistance to Defense, Aviation and Chemical Construction ("OSOVIAHIM"), former leaders and board members of former joint stock companies "Product" and "Lesoprodukt", Latvian citizen, as well as the Latvians came from Latvia as tourists and remained in the USSR, were subject to arrest.
It was also stipulated that the examination and consideration of the cases should be carried out subject to clause 6 of Operative Order No. 00485, according to which the sentences as to the persons belonging to so called "first category" (execution) should be executed immediately.
In Ukraine during the "Great Terror" 1937 - 1938 according to incomplete data, from June 2, 1937 to January 15, 1938, the number of people arrested for "Latvian espionage and counter-revolution" amounted to 1,743 people.