In the aftermath of the German and Soviet invasion of Poland, which took place in September 1939, the territory of Poland was divided between Nazi Germany and the Soviet Union. The Soviets had ceased to recognise the Polish state at the start of the invasion.Telegrams sent by Schulenburg, German ambassador to the Soviet Union, from Moscow to the German Foreign Office: No. 317 of 10 September 1939, No. 371 of 16 September 1939, No. 372 of 17 September 1939. The Avalon Project, Yale Law School. Retrieved 14 November 2006.1939 wrzesień 17, Moskwa Nota rządu sowieckiego nie przyjęta przez ambasadora Wacława Grzybowskiego (Note of the Soviet government to the Polish government on 17 September 1939, refused by Polish ambassador Wacław Grzybowski). Retrieved 15 November 2006. Since 1939 German and Soviet officials coordinated their Poland-related policies and repressive actions. For nearly two years following the invasion, the two occupiers continued to discuss bilateral plans for dealing with the Polish resistance during Gestapo-NKVD Conferences until Germany's Operation Barbarossa against the Soviet Union, in June 1941."Terminal horror suffered by so many millions of innocent Jewish, Slavic, and other European peoples as a result of this meeting of evil minds is an indelible stain on the history and integrity of Western civilization, with all of its humanitarian pretensions" (Note: "this meeting" refers to the most famous third (Zakopane) conference).Conquest, Robert (1991). Stalin: Breaker of Nations, New York, N.Y.: Viking.

The Molotov–Ribbentrop Pact was broken and the new war erupted, the Soviets had already arrested and imprisoned about 500,000 Polish nationals in the Kresy macroregion including civic officials, military personnel and all other "enemies of the people" such as clergy and the Polish educators: about one in ten of all adult males. There is some controversy as to whether the Soviet Union's policies were harsher than those of Nazi Germany until that time."In the 1939–1941 period alone, Soviet-inflicted suffering on all citizens in Poland exceeded that of Nazi-inflicted suffering on all citizens. (...) The Soviet-imposed myth about "Communist heroes of resistance" enabled them for decades to avoid the painful questions faced long ago by other Western countries." Johanna Granville, H-Net Review of Jan T. Gross. Revolution from Abroad.Citing Norman Davies' passage from God's Playground, Piotrowski writes: "In many ways, the work of Soviet NKVD in Eastern Poland proved far more destructive than that of Gestapo." An estimated 150,000 Polish citizens were killed by Soviet repressions.

Aftermath of the Soviet invasion of Poland

The Soviet Union took over 52.1% of the territory of Poland (circa 200,000 km²) with over 13,700,000 citizens at the end of the Polish Defensive War. Regarding the ethnic composition of these areas: ca. 5.1 million or 38% of the population were Polish by ethnicity (wrote Elżbieta Trela-Mazur), with 37% Ukrainians, 14.5% Belarusians, 8.4% Jews, 0.9% Russians and 0.6% Germans. There were also 336,000 refugees from areas occupied by Germany, most of them Jews (198,000).. Also in: Trela-Mazur 1997, Wrocławskie Studia Wschodnie, Wrocław. All Polish territories occupied by USSR were annexed to the Soviet Union with the exception of the area of Wilno, which was transferred to Lithuania.

On 28 September 1939, the Soviet Union and Germany had changed the secret terms of the Molotov–Ribbentrop Pact. The formerly sovereign Lithuania was moved into the Soviet sphere of influence and absorbed into the USSR as the brand new Lithuanian SSR among the Soviet republics. The demarcation line across the center of Poland was shifted to the east, giving Germany more Polish territory. (September Campaign 1939) from PWN Encyklopedia. Internet Archive, mid-2006. Retrieved 16 July 2007. By this new and final arrangement – often described as a fourth partition of Poland, the Soviet Union secured the lands east of the rivers Pisa, Narew, Bug and San. The area amounted to about 200,000 square kilometres, which was inhabited by 13.5 million formerly Polish citizens.Gross 1997, p. 17.

Initially, the Soviet occupation gained support among some citizens of the Second Polish Republic. Some members of the Ukrainian population welcomed the unification with Soviet Ukraine. The Ukrainians had failed to achieve independence in 1919 when their attempt at self-determination was crushed during the Polish–Soviet and Polish-Ukrainian Wars. Also, there were pre-war Polish citizens who saw the Soviet NKVD presence as an opportunity to start political and social agitation. Many of them committed treason against the Polish state by assisting in round-ups and executions of Polish officials. Their enthusiasm however faded with time as it became clear that the Soviet repressions were aimed at all peoples equally.

Soviet rule

The Soviet Union never officially declared war on Poland and ceased to recognise the Polish state at the start of the invasion. The Soviets did not classify Polish military personnel as prisoners of war, but as rebels against the new Soviet government in today's Western Ukraine and West Belarus. The NKVD and other Soviet agencies asserted their control in 1939 as an inherent part of the Sovietization of Kresy. Approximately 250,000 Polish prisoners of war were captured by the USSR during and after the invasion of Poland.Encyklopedia PWN 'KAMPANIA WRZEŚNIOWA 1939' , last retrieved on 10 December 2005, Polish language As the Soviet Union had not signed international conventions on rules of war, the Polish prisoners were denied legal status. The Soviet forces murdered almost all captured officers, and sent numerous ordinary soldiers to the Soviet Gulag.Out of the original group of Polish prisoners of war sent in large number to the labour camps were some 25,000 ordinary soldiers separated from the rest of their colleagues and imprisoned in a work camp in Równe, where they were forced to build a road. See: In one notorious atrocity ordered by Stalin, the Soviet secret police systematically shot and killed 22,000 Poles in a remote area during the Katyn massacre. Among some 14,471 victims were top Polish Army officers, including political leaders, government officials, and intellectuals. Some 4,254 dead bodies were uncovered in mass graves in Katyn Forest by the Nazis in 1943, who invited an international group of neutral representatives and doctors to examine the corpses and confirm the Soviet guilt. 22,000 Polish military personnel and civilians were killed in the Katyn massacre,Fischer, Benjamin B., ""The Katyn Controversy: Stalin's Killing Field ", Studies in Intelligence, Winter 1999–2000. Retrieved 16 July 2007. but thousands of others were victims of NKVD massacres of prisoners in mid-1941, before the German advance across the Soviet occupation zone.

In total, the Soviets killed tens of thousands of Polish prisoners of war. Many of them, like General Józef Olszyna-Wilczyński, captured, interrogated and shot on 22 September, were killed during the 1939 campaign.Sanford 2005, p. 23; also in Olszyna-Wilczyński Józef Konstanty , Encyklopedia PWN. Retrieved 14 November 2006. Polish Institute of National Remembrance. Internet Archive, 16.10.03. Retrieved 16 July 2007. On 24 September, 1939, the Soviets killed 42 staff and patients of a Polish military hospital in the village of Grabowiec, near Zamość. Rozstrzelany Szpital (Executed Hospital). Tygodnik Zamojski, 15 September 2004. Retrieved 28 November 2006. The Soviets also executed all the Polish officers they captured after the Battle of Szack, on 28 September. Szack. Encyklopedia Interia. Retrieved 28 November 2006.

The Soviet authorities regarded service to the prewar Polish state as a "crime against revolution" and "counter-revolutionary activity", and proceeded to arrest large numbers of Polish intelligentsia, former officials, politicians, civil servants and scientists, intellectuals and the clergy, as well as ordinary people thought to pose a threat to Soviet rule. In the two years between the invasion of Poland and the 1941 attack on USSR by Germany, the Soviets arrested and imprisoned about 500,000 Poles. This was about one in ten of all adult males. The arrested members of the Polish intelligentsia included former prime ministers Leon Kozłowski and Aleksander Prystor, Stanisław Grabski and Stanisław Głąbiński, and the Baczewski family. Initially aimed primarily at possible political opponents, by January 1940 the NKVD's campaign was also directed against potential allies, including Polish Communists and Socialists. Those arrested included Władysław Broniewski, Aleksander Wat, Tadeusz Peiper, Leopold Lewin, Anatol Stern, Teodor Parnicki, Marian Czuchnowski and many others. The Soviet NKVD executed about 65,000 imprisoned Poles after being subjected to show trials.

The number of Poles who died due to Soviet repressions in the period 1939–1941 is estimated by authors associated with the Polish Institute of National Remembrance, who uncritically uphold the 1947 official figures for Polish wartime losses, as at least 150,000.AFP / Expatica (30 August 2009), Polish experts lower nation's WWII death toll , Expatica Communications BV.Tomasz Szarota & Wojciech Materski (2009), Polska 1939–1945. Straty osobowe i ofiary represji pod dwiema okupacjami, Warsaw: Institute of National Remembrance, (Excerpt reproduced in digital form). According to other scholars, who depart from demographic data and take into account the population Poland lost through post-war citizenship changes, the total figure of Soviet-inflicted Polish deaths in the entire World War II period (1939–1945) probably did not exceed 100,000.

Mass deportations to the East

Approximately 100,000 Polish citizens were arrested during the two years of Soviet occupation.Karta Centre, REPRESJE 1939-41 Aresztowani na Kresach Wschodnich (Repressions 1939-41. Arrested on the Eastern Borderlands.) Ośrodek Karta. Last accessed on 15 November 2006. The prisons soon got severely overcrowded, with all detainees accused of anti-Soviet activities. The NKVD had to open dozens of ad-hoc prison sites in almost all towns of the region. The wave of arrests and mock convictions contributed to the forced resettlement of large categories of people ("kulaks", Polish civil servants, forest workers, university professors, "osadniks") to the Gulag labour camps and exile settlements in remote areas of the Soviet Union. Altogether the Soviets sent roughly a million people from Poland to Siberia.The actual number of deported in the period of 1939–1941 remains unknown and various estimates vary from 350,000 ( Encyklopedia PWN 'OKUPACJA SOWIECKA W POLSCE 1939–41' , last retrieved on March 14, 2006, Polish language) to over 2 million (mostly World War II estimates by the underground). The earlier number is based on records made by the NKVD and does not include roughly 180,000 prisoners of war, also in Soviet captivity. Most modern historians estimate the number of all people deported from areas taken by Soviet Union during this period at between 800,000 and 1,500,000; for example R. J. Rummel gives the number of 1,200,000 million; Tony Kushner and Katharine Knox give 1,500,000 in their Refugees in an Age of Genocide, p.219; in his Lethal Politics: Soviet Genocide and Mass Murder Since 1917, p.132. See also: and According to Norman Davies, almost half had died by the time the Sikorski-Mayski Agreement had been signed in 1941. Around 55% of the deportees to Siberia and Soviet Central Asia were Polish women,B. G. Smith. The Oxford Encyclopedia of Women in World History: 4 Volume Set. Oxford University Press. 2008 p. 470. for whom sexual violence (rape, forced prostitution) was part of the experience of Soviet penal institutions, compounded by the traditional taboos of Polish society that prevented women from discussing their plight "while preserving their dignity".