Polish prisoners of war in the Soviet Union after 1939

[3][4] During the Red Army's rapid advance, about 6,000–7,000 Polish soldiers died in the fighting,[5] Official Soviet estimate for the number of POWs taken during th campaign was 190,584 and is treated as reliable by some historians.

Lower estimate has been given as around 125,000 ;[6] according to the higher ones, 230,000–450,000[7] were taken prisoner—230,000 immediately after the campaign and 70,000 more when the Soviets annexed the Baltic States and assumed custody of Polish troops interned there[5][8][9][10] (12,000 in Lithuania).

[2] Some Polish soldiers were murdered shortly after capture, like General Józef Olszyna-Wilczyński, who was taken prisoner, interrogated and shot on September 22, during the invasion itself.

[2][12][13] On September 24, the Soviets murdered forty-two staff and patients at a Polish military hospital in the village of Grabowiec near Zamość.

[18] Once at the camps, from October 1939 to February 1940, the Poles were subjected to lengthy interrogations and constant political agitation by NKVD officers such as Vasily Zarubin.

[1] On March 5, 1940, a note to Joseph Stalin from Beria saw the members of the Soviet Politburo — Stalin, Vyacheslav Molotov, Lazar Kaganovich, Mikhail Kalinin, Kliment Voroshilov, Anastas Mikoyan and Beria — signed an order for the execution of "nationalists and counter-revolutionaries" kept at camps and prisons in western Ukraine and Belarus.

This execution became known as the Katyn massacre, where 22,000 perished[1][2] Diplomatic relations were, however, re-established in 1941 after the German invasion of the Soviet Union forced Joseph Stalin to look for allies.

Relatively few were sent to the Soviet Union (although there were notable exceptions, see Trial of the Sixteen); most were transferred to the Polish communist security forces and prisons, or enlisted in the Berling Army.