On 14 May 1948, when the British Mandate expired, the Zionist leadership declared the State of Israel. In the 1948 Arab-Israeli War which immediately followed, the armies of Egypt, Syria, Transjordan, Lebanon, Iraq, and Saudi Arabia intervened and were defeated by Israel. About 800,000 Palestinians fled from areas annexed by Israel and became refugees in neighbouring countries, thus creating the Palestinian problem, which has troubled the region ever since. Approximately two-thirds of 758,000-866,000 of the Jews expelled or who fled from Arab lands after 1948 were absorbed and naturalized by the State of Israel.