Why did Stalin cut off rail and road links to Berlin and how did America react?

Stalin cut off rail and road links to Berlin in June 1948 to exert control over the entire city and force the Western Allies to abandon their plans for a separate West German state. In response, America and its allies initiated the Berlin Airlift, supplying West Berlin with food, fuel, and other essentials via air transport to counteract the Soviet blockade. This operation showcased the West's commitment to defending Berlin and resisting Soviet expansion in Europe. Ultimately, the airlift succeeded in sustaining the city until the blockade was lifted in May 1949.