The Red Army invaded Poland from the east on 17 September after several calls by Germany to do so .
On August 23 , the Soviets signed the Molotov -- Ribbentrop Pact with Nazi Germany , and on 1 September , the Germans invaded Poland from the west .
The Red Army invaded Poland from the east on 17 September after several calls by Nazi Germany to do so .
On August 23 , the Soviets signed the Molotov -- Ribbentrop Pact with Nazi Germany , and on 1 September , the Germans invaded Poland from the west .