Zaire, officially the Democratic Republic of the Congo from 1965 to 1971 and the Republic of Zaire from 1971 to 1997, was the Congolese state in Central Africa headed by Mobutu Sese Seko from 1965 to 1997. It was, by area, the third-largest country in Africa after Sudan and Algeria, and the 11th-largest country in the world from 1965 to 1991. With a population of over 23 million, Zaire was the most populous Francophone country in Africa. Zaire was strategically important to the West during the Cold War, particularly the U.S., as a counterbalance to Soviet influence in Africa. The U.S. and its allies supported the Mobutu regime with military and economic aid to prevent the spread of communism which made it a key player for U.S. involvement in Africa.