As part of the 19th-century Zionist movement, Jews had begun settling in Palestine as early as 1820. This effort to establish a Jewish homeland received British approval in the Balfour Declaration of 1917. During the 1930s, Jews persecuted by the Hitler regime poured into Palestine. The postwar acknowledgment of the Holocaust?Hitler's genocide of 6 million Jews?increased international interest in and sympathy for the cause of Zionism. However, Arabs in Palestine and surrounding countries bitterly opposed prewar and postwar proposals to partition Palestine into Arab and Jewish sectors. The British mandate to govern Palestine ended after the war, and, in 1947, the UN voted to partition Palestine. When the British officially withdrew on May 14, 1948, the Jewish National Council proclaimed the State of Israel.
U.S. recognition came within hours. The next day, Arab forces from Egypt, Jordan, Syria, Lebanon, and Iraq invaded the new nation. By the cease-fire on Jan. 7, 1949, Israel had increased its original territory by 50%, taking western Galilee, a broad corridor through central Palestine to Jerusalem, and part of modern Jerusalem. Chaim Weizmann and David Ben-Gurion became Israel's first president and prime minister. The new government was admitted to the UN on May 11, 1949.