In 1968, Eastern Bloc member Czechoslovakia attempted the reforms of the Prague Spring and was subsequently invaded by the Soviet Union and other Warsaw Pact members, who reinstated the Soviet model. By 1973, the US had withdrawn from the Vietnam War. While communists gained power in some South East Asian countries, they were divided by the Sino-Soviet Split, with China moving closer to the Western camp, following US President Richard Nixon's visit to China. In the 1960s and 1970s, the Third World was increasingly divided between governments backed by the Soviets (such as Libya , Iraq , Syria , Egypt and South Yemen.) governments backed by NATO (such as Saudi Arabia), and a growing camp of non-aligned nations.