When renewed Arab rioting broke out in Jaffa in 1936 and soon spread throughout Palestine, the Mandate authorities--realizing that they could not defend every Jewish settlement--authorized the creation of the Jewish Settlement Police, also known as Notrim - who were trained, armed, and paid by the British. In 1938 a British intelligence officer, Captain Orde Charles Wingate, organized three counter guerrilla units, called special night squads, manned by British and Jewish personnel. As both of these organizations contained a large number of Haganah members, their formation greatly increased the assets of the Haganah while providing a legal basis for much of their activities. Although these nearly continuous disturbances from 1936 to 1939 cost the lives of nearly 600 Jews and more than 5,000 Arabs, Israeli observers have pointed out that Jewish casualties would have been far greater were it not for the increasing effectiveness of these paramilitary units. .
During these disturbances, the Haganah's policy of havlaga, or self-restraint, under which retaliation against the Arab community at large was strictly forbidden, was not aggressive enough for some. Under Vladimir (Zeev) Jabotinsky and later Menachem Begin, these dissidents in 1937 established the National Military Organization (Irgun Zvai Leumi, known both as the Irgun and by the acronym Etzel). Initially the Irgun waged a campaign of terror, sabotage, and reprisal against the Arabs. After the British government issued a white paper in May 1939 extending the Mandate for ten years and placing limits on Jewish immigration, however, the Irgun turned its terrorist activities against the British troops in Palestine in an all-out struggle against the Mandate authority. .
With the outbreak of World War II, Irgun leaders settled on a policy of cooperation with the British in the war effort; but a hard core within the organization opposed the policy and accordingly split off from the larger body.
