The Third (1919–23) and Fourth Aliyahs (1924–29) brought an additional 100,000 Jews to Palestine. Finally, 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 during which the British Mandate authorities alongside the Zionist militias of 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 33% of the total population. On July 22, 1946, Irgun attacked the British administrative headquarters for Palestine, which was housed in the southern wing of the King David Hotel in Jerusalem. 91 people of various nationalities were killed and 46 were injured. The hotel was the site of the central offices of the British Mandatory authorities of Palestine, principally the Secretariat of the Government of Palestine and the Headquarters of the British Armed Forces in Palestine and Transjordan. The attack initially had the approval of the Haganah (the principal Jewish paramilitary group in Palestine). It was conceived as a response to Operation Agatha (a series of widespread raids, including one on the Jewish Agency, conducted by the British authorities) and was the deadliest directed at the British during the Mandate era (1920–1948).