 U.S. forces generally held onto these gains within Germany until July 1945, when under orders from President Harry S. Truman, and against the advice of British Prime Minister Winston Churchill the U.S. forces withdrew to the Yalta agreement boundaries dividing Germany into occupation zones.It is worth noting that the Soviet Union may not have allowed American and British forces into Berlin, which was completely under their control, if the U.S. had not honored the Yalta agreement boundaries.The German areas relinquished by American troops became part of the Soviet-dominated East Germany.