of German origin in case of German invasion, which was immediately implemented after the actual invasion by forcibly transferring 1.2 million citizens of German origin from European Russia to Siberia and Soviet Central Asia. Aftermath Hitler breaks the Pact Nazi Germany terminated the Molotov–Ribbentrop Pact with its invasion of the Soviet Union in Operation Barbarossa on June 22, 1941. After the launch of the invasion, the territories that had been gained by the Soviet Union as a result of the Molotov–Ribbentrop Pact were lost in a matter of weeks. In the three weeks following the breaking of the Pact, the Soviet Union attempted to defend itself against vast German advances; in the process, the Soviet Union suffered 750,000 casualties, and lost 10,000 tanks and 4,000 aircraft. Within six months, the Soviet military had suffered 4.3 million casualties and the Germans had captured three million Soviet prisoners, two million of which would die in German captivity by February 1942. German forces had advanced 1,050 miles (1,690 kilometers), and maintained a linearly-measured front of 1,900 miles (3,058 kilometers). Denial of the Secret Protocol's existence by the Soviet Union German officials found a microfilmed copy of the secret protocols of the Molotov-Ribbentrop Pact in 1945 and provided it to United States military forces. Despite publication of the recovered copy in western media, for decades it was the official policy of the Soviet Union to deny the existence of the secret protocol. After the Baltic Way demonstrations of August 23, 1989, a Soviet commission concluded in December 1989 that the protocol had existed. In 1992, only after the dissolution of the Soviet Union, the document itself was declassified. Post-war commentary regarding the timing of rapprochement After the war, historians have argued about the start of Soviet-German rapprochement. There are many conflicting points of view in historiography as to when the Soviet side began to seek rapprochement and when the secret political negotiations started. Some scholars argue that for a long time the collective security doctrine was a sincere and unanimous position of the Soviet leadership, pursuing a purely defensive line, whereas others contend that from the very beginning the Soviet Union intended to cooperate with Nazi Germany, collective security being merely tactical counter to some unfriendly German moves. However, perhaps Moscow sought to avoid a great war in Europe because it was not strong enough to fight an offensive war; but there was much