During the 1960s, DIA analysts focused on China's detonation of an atomic bomb and the launching of its Cultural Revolution; increasing unrest among African and South Asian nations; fighting in Cyprus and Kashmir; and the missile gap between the U.S. and the Soviet Union. In the late 1960s, crises that tested intelligence responsiveness included: the Tet Offensive in Vietnam; the Six-Day War between Egypt and Israel; continuing troubles in Africa, particularly Nigeria; North Korea's seizure of the ; and the Warsaw Pact invasion of Czechoslovakia.