Zaire, officially the Democratic Republic of the Congo from 1965 to 1971 and Republic of Zaire from 1971 to 1997, was a country 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.