Before the German invasion of the USSR, the USSR, which had recently annexed parts of Poland as well as the Baltic states, carried out the Katyn massacre of 1940, a series of mass executions of over 20,000 Polish citizens, including 8,000 Polish Army officers, and smaller scale massacres of Baltic states officers.
[1]: 237 While the Soviet Union did not consider itself engaged in World War II until Operation Barbarossa in 1941, already on 17 September 1939 it invaded Poland, alongside Germany, in accordance with the Molotov–Ribbentrop Pact.
[3]: 41 [5][6]: 76–88 The highest profile victims of Soviet atrocities of that period included General Józef Olszyna-Wilczyński, who was taken prisoner, interrogated and shot together with his adjutant on September 22.
[6]: 55 On September 25, the Soviets murdered staff and patients at a Polish military hospital in the village of Grabowiec near Zamość;[5][12] Tadeusz Piotrowski mentions the death of 12 officers in this context.
According to Edmund Nowak, they "were decimated... by inhumane treatment, extremely hard work conditions, cold, diseases and chronic hunger".
[18][17] Once at the camps, from October 1939 to February 1940, the Poles were subjected to lengthy interrogations and constant political pressure to accept the dogma of communism and friendship of the Soviet Union.
If a prisoner could not be induced to quickly adopt a pro-Soviet attitude, he was declared a "hardened and uncompromising enemy of Soviet authority".
According to Alfred de Zayas, "For the entire duration of the Russian campaign, reports of torture and murder of German prisoners did not cease.
At the same time... it has made use of the following means of camouflage: in a Red Army order that bears the approval of the Council of People's Commissars, dated 1 July 1941, the norms of international law are made public, which the Red Army in the spirit of the Hague Regulations on Land Warfare are supposed to follow...
"[29]: 178 According to the depositions, Soviet massacres of German, Italian, Spanish, and other Axis POWs were often incited by unit commissars, who claimed to be acting under orders from Stalin and the Politburo.
[29]: 162–210 Unlike with the execution of Polish POWs at Katyn, however, no such directive attributed to Stalin or top Soviet officials, concerning Germans, have been found.
However, despite the non-existence of such order, many lower ranking officers and soldiers, encouraged by brutal and simplistic propaganda, believed it exists, or that the execution of German POWs is unofficially expected or sanctioned.
[30][31] Soon afterward, Soviet officials realized that such approach, leading to POW executions, was counterproductive, and reduced the chance of German soldiers surrendering; consequently, in February of 1942, Stalin, in another speech, explicitly encouraged taking prisoners.
Grunewald also pointed out that Soviet authorities generally "did not respond by taking similar actions against their prisoners" and to a large extent followed the standards of the Geneva Convention (despite the USSR not being a signatory) by segregating officers from enlisted soldiers, exempting officers from labour and trying to give POWs rations equal to those of equivalent rank in their own army.
He note that the situation of German and other Axis POWs improved in the later years of the war, as Soviets started to integrate them more efficiently (and purposively) into the economy of USSR as forced laborers.
[34]: 261 The death rate of German soldiers held by Soviet Union has been estimated at 15% by Mark Edele,[31] and at 35.8% by Niall Ferguson.
[29]: 180–186 The Massacre of Grischino was committed by an armoured division of the Red Army in February 1943 (Soviet 4th Guards Tank Corps) in the eastern Ukrainian town of Krasnoarmeyskoye (also known as Grishchino).
In the cellar of the main train station around 120 Germans were herded into a large storage room and then mowed down with machine guns.
The remainder suffered from various discriminations; including some (about 6% of the total repatriated Soviet citizens, civilians and POW, who were "transferred to the NKVD ‘for disposal’,".
[31] However, several scholars noted that the Soviet Union, while publicly declaring its support for humane treatment of POWs, routinely ignored them, committing various atrocities.
However, unlike the other authors cited above, she adduced that motive as an explanation of genuine efforts on the part of the USSR to treat German prisoners well.