The treaty was officially signed and enacted on 20 September 1955. Among its stipulations were an agreement that "the Soviet troops temporarily stationed in the GDR with the consent of its government do not interfere in the country’s domestic affairs and social and political life." Also stated was that the GDR was to continue exercising protection and control of its borders, but until a further agreement was reached, the Soviet Army Command in Germany was to "control the movement of American, French, and British personnel and cargoes entering and exiting West Berlin. This provision may have been added in case the Soviet Union wished to try to force the Western Allies to withdraw from West Berlin by cutting off the railways and roads leading in from East Germany, as they tried, and failed to do in 1948-49 during the Berlin Airlift, in response to the Western Allies issuing a new currency into their sector, further destabilizing the East German economy.