In accordance with the Soviet-Nazi Molotov–Ribbentrop Pact of 23 August 1939, the Red Army invaded Poland on 17 September 1939, after the Nazi invasion on 1 September 1939. On 30 November the Red Army also attacked Finland, in the Winter War of 1939–1940. By autumn 1940, after conquering its portion of Poland, the Third Reich shared an extensive border with USSR, with whom it remained neutrally bound by their non-aggression pact and trade agreements. Another consequence of the Molotov-Ribbentrop Pact was the Soviet occupation of Bessarabia and northern Bukovina, carried out by the Southern Front in June–July 1940 and Soviet occupation of the Baltic states (1940). These conquests also added to the border the Soviet Union shared with Nazi-controlled areas. For Adolf Hitler, the circumstance was no dilemma, because the "Drang nach Osten" ("Drive towards the East") policy secretly remained in force, culminating on 18 December 1940 with "Directive No. 21, Operation Barbarossa", approved on 3 February 1941, and scheduled for mid-May 1941.