During the Suez Crisis of 1956, the idea promoted by Canada in 1945 of a United Nations military force returned to the fore. The conflict involving Britain, France, Israel and Egypt quickly developed into a potential flashpoint between the emerging 'superpowers' of the United States and the Soviet Union as the Soviets made intimations that they would militarily support Egypt's cause. The Soviets went as far as to say they would be willing to use "all types of modern weapons of destruction" on London and Paris – an overt threat of nuclear attack. Canadian diplomat Lester B. Pearson re-introduced then Prime Minister Louis St. Laurent's UN military force concept in the form of an 'Emergency Force' that would intercede and divide the combatants, and form a buffer zone or 'human shield' between the opposing forces. Pearson's United Nations Emergency Force (UNEF) – the first peacekeeping force, was deployed to separate the combatants and a cease-fire and resolution was drawn up to end the hostilities.