In February 1945, the three leaders met at the Yalta Conference. Roosevelt and Churchill conceded to Stalin's demand that Germany pay the Soviet Union 20 billion dollars in reparations, and that his country be permitted to annex Sakhalin and the Kuril Islands in exchange for entering the war against Japan. An agreement was also made that a post-war Polish government should be a coalition consisting of both communist and conservative elements. Privately, Stalin sought to ensure that Poland would come fully under Soviet influence. The Red Army withheld assistance to Polish resistance fighters battling the Germans in the Warsaw Uprising, with Stalin believing that any victorious Polish militants could interfere with his aspirations to dominate Poland through a future Marxist government. Although concealing his desires from the other Allied leaders, Stalin placed great emphasis on capturing Berlin first, believing that this would enable him to bring more of Europe under long-term Soviet control. Churchill was concerned that this was the case and unsuccessfully tried to convince the U.S. that the Western Allies should pursue the same goal.