This group, led by Avraham Stern, formed the Fighters for Israel's Freedom (Lohamei Herut Israel--Lehi), known as the Stern Gang. The Stern Gang, which included Begin and later Yitzhak Shamir, specialized in the assassination of British and other officials. At their peaks, the Irgun contained about 4,000 men; the Stern Gang, 200 to 300. Defeat of Nazi Germany in 1945 precipitated a resumption of anti-British activities by both Haganah and Irgun in pursuance of their common ultimate goal, the establishment of a national home and the creation of a sovereign Jewish state. .
During World War II, about 32,000 Palestinian Jews, both men and women, volunteered for the British army. In 1944 about 5,000 of these were formed into the Jewish Brigade, which fought successfully in Italy in 1945. With so many of its members serving abroad, the ranks of the Haganah were depleted, and in 1941 its leaders decided to raise a mobile force--the Palmach (abbreviation of Pelugot Mahatz -Shock Forces) - of approximately 3,000 full-time soldiers, whose mission was to defend the Yishuv. Trained with the aid of the British, the Palmach was the first full-time standing Jewish army in more than 2,000 years and is considered the direct forerunner to the IDF. For many years, the vast majority of IDF officers were veterans of either the Palmach or the Jewish Brigade. .
When Israel achieved its independence on May 14, 1948, the Haganah became the de facto Israeli army. On that day, the country was invaded by the regular forces of Egypt, Lebanon, Iraq, and Syria. Eleven days later, Israel's provisional government issued an order that provided the legal framework for the country's armed forces. The order established the official name Zvah Haganah Le Yisrael and outlawed the existence of any other military force within Israel. .
The dissident Irgun and Stern Gang were reluctant to disband. Fighting between Irgun and regular military forces broke out on June 21 when the supply ship Altalena arrived at Tel Aviv with 900 men and a load of arms and ammunition for the Irgun.
