At what point were the soviets given primary responsibility for the balkans

Balkan region territory extends in different European countries. The Soviet wanted to intervene with these territories and lead the Communist Balkan Federation.  However, it received deviating responses from some of the territories especially Yugoslavia. 
To gain hold of the economic structures within the Balkan region, the Soviet opened the Council for Mutual Economic Assistance in 1949 and also made the WarSaw Treaty Organization.