Recurring pro-Kremlin disinformation narrative distorting the events of the World War II.
In his op-ed for Politico, Morawiecki notes that "liberation of Warsaw" is an overgenerous term, particularly in the context of Soviet actions before, during, and after the Second World War.
On 17 September 1939, after Nazi Germany attacked Poland, the USSR invaded and occupied the eastern half of Poland, in accordance with the provisions of the Nazi-Soviet Pact concluded in August of the same year and effective until summer 1941. During that time, Nazi and Soviet officials held regular joint conferences in occupied Poland, exchanging tips on how to deal with potential resistance posed by the Polish intelligentsia and military brass. By June 1941, the Soviet Union had managed to deport over 250,000 Poles to Siberia and Central Asia, murder 22,000 Polish Army officers and imprison half a million citizens.
Long after the German invasion of Soviet territory, Moscow continued to deny support to the anti-Nazi resistance in Poland, most notably during the Warsaw Uprising which claimed 200,000 lives.
After the Nazi defeat, the USSR installed a communist government in Warsaw, effectively delaying Polish independence until 1989.
The claim that 600,000 Soviet troops died during the liberation of Poland is misleading and inconsistent with other Russian claims. A July 2017 statement by the Russian Foreign Ministry reads that this number pertains to Soviet casualties sustained "in battles against the enemy on the territory of this country" between 1944-45. The following month, Russia's ambassador in Poland said that the estimate concerns Red Army losses on present-day Polish territory, one-third of which belonged to the Third Reich before 1945. In 2019, Russia's Defence Ministry said that the number of fallen Soviet troops in the same period was actually 477,000, before bumping up their estimate to 600,000 in 2020, citing a new batch of "archival documents".
That said, the most significant Soviet operation which could be credited with liberating Poland from Nazism was the Vistula-Oder offensive, which resulted in the displacement of Nazi troops from Warsaw and other major Polish cities between 12 January and 2 February 1945. According to Soviet data, the operation claimed the lives of 43,251 Red Army troops.
See the debunk, 200 000 Soviet soldiers gave their lives, liberating Warsaw from Nazis for another example of pro-Kremlin outlets manipulating WWII death statistics.