After relations between the Soviet Union and Yugoslavia broke down in 1948, the U.S. Central Intelligence Agency (CIA) devoted a good deal of attention to Yugoslavia. Initially, however, the Truman administration was reluctant to provide extensive security assistance to the regime of Josip Broz Tito, who until 1948 had been a brutal Stalinist. The outbreak of the Korean War in June 1950 changed the situation. The United States developed much closer political, economic, and military ties with Yugoslavia, and the CIA established a formal agreement of cooperation with the Yugoslav Ministry of State Security, especially on intelligence-sharing and covert operations. U.S. officials were particularly concerned about ensuring that Yugoslavia would be able to defend itself, if necessary, against a Soviet invasion.