Following the Nazi-Soviet Pact (23 August 1939) and until the eve of the German invasion of the USSR on 22 June 1941, the same repressive practices to which Soviet society had been widely subjected since 1929 were exported to the recently annexed western territories. The brutal manner of their implementation deeply scarred Polish, Latvian, Lithuanian and Estonian societies, now subjected to “sovietization”. For the occupying authorities, however, these policies merely duplicated, in an almost routine fashion, measures commonly applied to Soviet citizens. The occupiers had to cross no further threshold of violence as they put them into practice.
The three main repressive measures were mass arrests, followed by labour camp sentences (approximately 110,000 arrested in occupied Poland); collective deportation (320,000 Poles, 80,000 Balts and Moldovans) in which deportees were treated as “special settlers” , subject to the same assignments and labour regime applied to this category of Soviet citizens; and the mass execution of the Polish elite (over 25,000).
(Text adapted from 2009 article by Nicolas Werth “Les crimes de masse sous Staline, 1930-1953”)
Those who had received land on the border with the USSR as compensation from the Polish State for service rendered during the Polish-Soviet war of 1920.
10-14 February: Deportation of 27,000 Polish families (139,600 people)
to 24 regions of the USSR, from Arkhangelsk to Irkutsk. In reality, those deported encompassed a far wider contingent than just the category of “military settlers and foresters”, including landowners, industrialists, civil servants and other “class enemies”.
5 March, Letter to Stalin from Beria, the People’s Commissar for Internal Affairs: soliciting the execution of 25,700 former members of the Polish elite – officers, senior officials, great landowners, industrialists, senior police officers and other “members of Polish counter-revolutionary organizations.”
April – Execution of 25,700 Poles, officers, senior officials, members of the military, civil and economic elites, who had been incarcerated in the three “special camps” of Kozelsk, Ostashkov and Starobelsk. Katyn was one of several locations where these executions took place.
2 APRIL. POLITBURO RESOLUTION
Deportation of three categories of Poles
 family members (of officers, senior officials, industrialists, great landowners who had already been arrested); (2) prostitutes; and (3) refugees from the western part of Poland (now under German occupation) who had crossed eastwards into the Soviet occupied zone.
12-13 April – Deportation to Kazakhstan of 61,000 people belonging to Poles belonging to one of the three “categories” defined by the April 2, 1940 Politburo Resolution.
28-29 June – Deportation to “special settlements” in Siberia of 75,000 Polish refugees from the German occupation zone who had crossed to the east, into the Soviet occupation zone.
16 MAY. POLITBURO RESOLUTION
Deportation of nine categories of people from Lithuania, Latvia, Estonia, Moldavia and those fleeing German-occupied Poland
(members of counter-revolutionary parties; former police officers, senior officials, judges and attorneys, landowners, industrialists, wholesale tradesmen; former officers; criminal elements; prostitutes; family members of categories 2 to 4; family members of category 1; Polish refugees) from the German occupation zone, from the three Baltic States (Lithuania, Latvia and Estonia), which had been absorbed by the USSR in 1940, and from Moldavia, which had been annexed to the USSR in August 1940.
22 May to 20 June – Implementation of the 4th great deportation planned by the Politburo Resolution of 16 May 1941. Within one month, 107,000 people were arrested, 86,000 of whom were deported to Siberia and Kazakhstan while the remainder were sent to Gulag labour camps.