<P> Shortly thereafter, Stalin instituted the Berlin Blockade (24 June 1948--12 May 1949), one of the first major crises of the Cold War, preventing food, materials and supplies from arriving in West Berlin . The United States, Britain, France, Canada, Australia, New Zealand and several other countries began the massive "Berlin airlift", supplying West Berlin with food and other provisions . </P> <P> The Soviets mounted a public relations campaign against the policy change . Once again the East Berlin communists attempted to disrupt the Berlin municipal elections (as they had done in the 1946 elections), which were held on 5 December 1948 and produced a turnout of 86.3% and an overwhelming victory for the non-communist parties . The results effectively divided the city into East and West versions of its former self . 300,000 Berliners demonstrated and urged the international airlift to continue, and US Air Force pilot Gail Halvorsen created "Operation Vittles", which supplied candy to German children . In May 1949, Stalin backed down and lifted the blockade . </P> <P> In 1952, Stalin repeatedly proposed a plan to unify East and West Germany under a single government chosen in elections supervised by the United Nations if the new Germany were to stay out of Western military alliances, but this proposal was turned down by the Western powers . Some sources dispute the sincerity of the proposal . </P> <P> Britain, France, the United States, Canada and other eight western European countries signed the North Atlantic Treaty of April 1949, establishing the North Atlantic Treaty Organization (NATO). That August, the first Soviet atomic device was detonated in Semipalatinsk, Kazakh SSR . Following Soviet refusals to participate in a German rebuilding effort set forth by western European countries in 1948, the US, Britain and France spearheaded the establishment of West Germany from the three Western zones of occupation in April 1949 . The Soviet Union proclaimed its zone of occupation in Germany the German Democratic Republic that October . </P>

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