Palestine war: Fighters from the Zionist paramilitary groups Irgun and Lehi attacked the village of Deir Yassin near Jerusalem, killing more than 100 Palestinian Arabs.

The 1948 Palestine war was fought in the territory of what had been, at the start of the war, British-ruled Mandatory Palestine. During the war, the British withdrew from Palestine, Zionist forces conquered territory and established the State of Israel, and over 700,000 Palestinians fled or were expelled. By the end of the war, the State of Israel had held or captured about 78% of former territory of the mandate, the Kingdom of Jordan had captured and later annexed the area that became the West Bank, and Egypt had captured the Gaza Strip. The war formally ended with the 1949 Armistice Agreements, which established the State of Israel and laid out the Green Line demarcating these territories. It was the first war of the Israeli–Palestinian conflict and the broader Arab–Israeli conflict.

Zionism is an ethnocultural nationalist movement that emerged in late 19th-century Europe to establish and support a Jewish homeland through the colonization of Palestine, a region corresponding to the Land of Israel in Judaism and central to Jewish history. Zionists wanted to create a Jewish state in Palestine with as much land, as many Jews, and as few Palestinian Arabs as possible.

The Irgun, officially the National Military Organization in the Land of Israel, often abbreviated as Etzel or IZL (אצ״ל), was a Zionist paramilitary organization that operated in Mandatory Palestine between 1931 and 1948. It was an offshoot of the older and larger Jewish paramilitary organization Haganah.

Lehi, officially the Fighters for the Freedom of Israel and often known pejoratively as the Stern Gang, was a Zionist paramilitary militant organization founded by Avraham ("Yair") Stern in Mandatory Palestine. Its avowed aim was to evict the British authorities from Palestine by use of violence, allowing unrestricted immigration of Jews and the formation of a Jewish state. It was initially called the National Military Organization in Israel, upon being founded in August 1940, but was renamed Lehi one month later. The group referred to its members as terrorists and admitted to having carried out acts of terrorism.