The four great powers occupied and controlled Austria after its liberation. Austrians were involved in Hitler's war crimes, yet Austrian diplomacy persuaded the world and its own population that Austria was a victim. While the Soviets concentrated on the economic exploitation of Austria, the Western powers feared a Communist takeover. American economic aid totalling $1.5 billion guaranteed the economic survival and political stability of Austria and 'balanced off' the same amount in reparations extracted by the Soviets from their zone. At the height of Cold War tensions, Western observers considered Austria 'Europe's Korea'. The re-armament of Austria was initiated before the German one - Austria became a 'secret ally' of the West. After eight years of negotiations the Austrian treaty was concluded in May 1955. Shrewd bilateral Austrian diplomacy with Stalin's successors in the Kremlin led to the breakthrough and demonstrated that the weak had leverage in manoeuvring between the superpowers.