7 August – 26 October 1946
Turkish Straits Crisis
Ever since March 1945 the Soviet Union had been placing pressure on the government of Turkey—which had remained neutral during World War II—to grant free access to Soviet ships through the straits which connect the Black Sea to the Mediterranean. On August 7, 1946, the Soviet government demanded that an international conference be held to discuss the question of control of the straits. To underscore their point they began a series of naval maneuvers in the Black Sea, and dispatched a substantial number of troops to the Balkans.

The Turkish government appealed to the West for aid, and on August 20, after consulting with his advisors, President Truman dispatched a naval task force to the area. Reassured by this, Turkey responded with a flat rejection of Soviet demands, and on October 9 both the United States and Great Britain sent notes to the Soviets reaffirming their support for Turkey. Later that month Moscow relented, sending a note in which they rescinded their demand for an international conference.

Link:
Russian Pressure: Basis for U.S. Aid to Turkey