The Soviet Union invaded Poland from the East two weeks earlier, on 17 September 1939, pursuant to the secret protocol of the Molotov–Ribbentrop Pact. The Red Army overran 52.1% of territory of Poland with over 13,700,000 inhabitants. The Soviet occupation zone included 5.1 million ethnic Poles (ca. 38%), 37% Ukrainians, 14.5% Belarusians, 8.4% Jews, 0.9% Russians and 0.6% Germans. There were also 336,000 refugees who escaped to eastern Poland from areas already occupied by Germany – most of them Polish Jews numbering at around 198,000.