Soviet annexation of Western Belorussia

On September 17, 1939 the Red Army entered Polish territory, acting on the basis of a secret clause of the Molotov–Ribbentrop Pact between the Soviet Union and Nazi Germany.

Soviet Union later denied the existence of this secret protocol, claiming that it was never allied with the German Reich, and acted independently to "protect" the Ukrainian and Belarusian minorities in the disintegrating Polish state.

[4] Immediately after entering Poland's territory, the Soviet army helped to set up "provisional administrations" in the cities and "peasant committees" in the villages in order to organize one-list elections to the new "People's Assembly of Western Belarus".

[citation needed] On November 14 the law on the admission of Western Belarus to the Byelorussian Soviet Socialist Republic was signed at an extraordinary session of the Supreme Council.

[11] In August 2009, on the occasion of the 70th anniversary of the Soviet invasion, the authoritative Polish Institute of National Remembrance announced that its researchers reduced the estimate of the number of people deported to Siberia to 320,000 in total.