 Growing economic differences combined with developing political tensions between the US and the Soviet Union (which would eventually develop into the Cold War) were manifested in the refusal in 1947 of the SMAD to take part in the USA's Marshall Plan.In March 1948, the United States, Britain and France met in London and agreed to unite the Western zones and to establish a West German republic.The Soviet Union responded by leaving the Allied Control Council, and prepared to create an East German state.