To end the four-power-control of Berlin, Soviet leader Chrustschow sends an ultimatum to the west: If there are no negotiations about the transformation of Berlin into a "free city", the USSR will hand over all their rights and responsibilities with regard to the city to the GDR. For example the control over the routes to the west by water, land and air.
The goal was to revoke the four-power control status of Berlin and drive the Western forces out of the city due to the massive flight movement that had started in the GDR.
The USA, Britain and France did not give in, Chrustschow shrunk back from the confrontation.

