PARIS (AP) _ Japanese diplomat Koichiro Matsuura was sworn in Monday as director-general of UNESCO and pledged to overhaul the troubled Paris-based agency.

In his inaugural speech, the first Asian to head the U.N. Educational, Scientific and Cultural Organization admitted the agency presented a ``challenging paradox.''

Matsuura, who takes over from Spain's Federico Mayor, said he has a duty ``to ensure that our institution fully discharge its great task as a true world service, responsible and accountable to the world and to the world's taxpayers.''

Founded in 1946 to fight intolerance and racism, UNESCO has been criticized as being badly managed, top-heavy and corrupt. Some critics have said it is little more than a talking shop for intellectuals.

``I propose that we streamline our activities within the limits of our budgets and closely focus upon those programs which are our true mandate _ not for the sake of fashionable austerity, but in order to make a real impact where best we may,'' Matsuura told delegates to UNESCO's 30th general conference.

One of UNESCO's most vocal critics has been the United States, which left the group in 1984 and has never returned.

Matsuura said he would work to win the Americans back.

``UNESCO must once more represent the whole world with no exceptions. I pledge to do my best to persuade those who would still stand outside to return or newly join,'' he said.

Born in Tokyo in 1937, Matsuura started his career at the Japanese Ministry for Foreign Affairs. He has served as ambassador to Andorra, Djibouti and most recently France.