The Third (1919–23) and Fourth Aliyahs (1924–29) brought an additional 100,000 Jews to Palestine. The rise of Nazism and the increasing persecution of Jews in 1930s Europe led to the Fifth Aliyah, with an influx of a quarter of a million Jews. This was a major cause of the Arab revolt of 1936–39, which was launched as a reaction to continued Jewish immigration and land purchases. Several hundred Jews and British security personnel were killed, while the British Mandate authorities alongside the Zionist militias of the Haganah and Irgun killed 5,032 Arabs and wounded 14,760, resulting in over ten percent of the adult male Palestinian Arab population killed, wounded, imprisoned or exiled. The British introduced restrictions on Jewish immigration to Palestine with the White Paper of 1939. With countries around the world turning away Jewish refugees fleeing the Holocaust, a clandestine movement known as Aliyah Bet was organized to bring Jews to Palestine. By the end of World War II, the Jewish population of Palestine had increased to 31% of the total population.