The first official UN peacekeeping force was deployed in the Sinai Peninsula in 1956, although a UN force had been monitoring the border between Israel and its neighbours since 1948.
The peacekeepers were to cover the withdrawal of British, French and Israeli forces from Egypt, following their invasion in the wake of the nationalisation of the Suez canal. The invading powers agreed to withdraw in return for certain promises, which the peacekeeping forces were to guarantee. The United Nations Emergency Force served as a buffer zone between the Egyptian and Israeli forces. They kept the peace for 10 years.
However, in 1967, President Nasser of Egypt ordered the UN troops to withdraw. They had no choice but to leave, and within days war broke out again. When Israel attacked on 5 June, 14 remaining UN soldiers were killed.