The northern half of East Prussia in the region of Königsberg was administratively assigned by the Potsdam Agreement to the Soviet Union, pending a final Peace Conference (with the commitment of Britain and the United States to support its incorporation into Russia); and was then annexed by the Soviet Union. The Free City of Danzig and the southern half of East Prussia were incorporated into and annexed by Poland; the Allies having assured the Polish government-in-exile of their support for this after the Tehran Conference in 1943. It was also agreed at Potsdam that Poland would receive all German lands east of the Oder-Neisse line, although the exact delimitation of the boundary was left to be resolved at an eventual Peace Conference. Under the wartime alliances of the United Kingdom with the Czechoslovak and Polish governments-in-exile, the British had agreed in July 1942 to support "..the General Principle of the transfer to Germany of German minorities in Central and South Eastern Europe after the war in cases where this seems necessary and desirable". In 1944 roughly 12.4 million ethnic Germans were living in territory that became part of post-war Poland and Soviet Union. Approximately 6 million fled or were evacuated before the Red Army occupied the area. Of the remainder, around 2 million died during the war or in its aftermath (1.4 million as military casualties; 600,000 as civilian deaths), 3.6 million were expelled by the Poles, one million declared themselves to be Poles, and 300,000 remained in Poland as Germans. The Sudetenland territories, surrendered to Germany by the Munich Agreement, were returned to Czechoslovakia; these territories containing a further 3 million ethnic Germans. 'Wild' expulsions from Czechoslovakia began immediately after the German surrender.