Yalta Conference 1945: a meeting (Feb. 4–11, 1945), at Yalta, Crimea, USSR, of British Prime Minister Winston Churchill, U.S. President Franklin Delano Roosevelt, and Soviet Premier Joseph Stalin. The Yalta conferees Conference demanded Germany's unconditional surrender. Plans were made for dividing Germany into four zones of occupation (American, British, French, and Soviet) under a unified control commission in Berlin, for war crimes trials (Nuremberg Trials), and for a study of the reparations question. Agreement was also reached on reorganizing the Polish Lublin government (supported by Stalin) "on a broader democratic basis" that would include members of Poland's London government-in-exile, which the Western Allies had supported. The conferees decided to ask China and France to join them in sponsoring the founding conference of the United Nations to be convened in San Francisco on Apr. 25, 1945; agreement was reached on using the veto system of voting in the projected Security Council. Future meetings of the foreign ministers of the "Big Three" were planned. The USSR secretly agreed to enter the war against Japan within three months of Germany's surrender and was promised S Sakhalin, the Kuril Islands, and an occupation zone in Korea. The secret agreement respecting the disposal of Japan's holdings also provided that the port of Dalian (Dairen) should be internationalized, that Port Arthur should be restored to its status before the 1904–5 Russo-Japanese War as a Russian naval base, and that the Manchurian railroads should be under joint Chinese-Soviet administration. China later protested that it was not informed of these decisions concerning its territory and that its sovereignty was infringed. The United States and Great Britain also agreed to recognize the autonomy of Outer Mongolia, and to admit Ukraine and Belorussia (Belarus) to the United Nations as full members.