 During the Berlin Blockade, which endured from June 1948 to May 1949, the Soviet checkpoint was closed.From 1950 onwards, the East German ' (later the ') performed the border control on the eastern side of the checkpoint, with the exception of the Soviet military, which escorted Allied military traffic to and from West Berlin.Due to the increasing tensions between the Western Allies and the Soviet Union during the Cold War, the border crossing was expanded extensively and security was increased during the following years.