With the end of World War II, Soviet domination of the Black Sea region was confirmed. The Soviet Union controlled the entire north and east of the Black Sea region while pro-Soviet regimes were installed in Romania and Bulgaria. As members of the Warsaw Pact, the Romanian and Bulgarian navies supplemented the strength of the Soviet Black Sea Fleet. Only Turkey remained outside the Soviet Black Sea security regime and the Soviets initially pressed for joint control of the Bosporus Straits with Turkey; a position which Turkey rejected. In 1952, Turkey decided to join NATO, placing the Bosporus Straits in the Western sphere of influence. Nevertheless, the terms of the Montreux Convention limited NATO's options with respect to directly reinforcing Turkey's position in the Black Sea. The Soviets, in turn, had some of their naval options in the Mediterranean restricted by the Montreux Convention limitations.