ATLANTA - Progressive leadership in some African states presents a big opportunity for development but donor countries and especially the United States must respond, World Bank President Paul Wolfowitz said on Monday.

Addressing an audience at the Federal Reserve Bank of Atlanta, Wolfowitz said an increasing number of African leaders were taking the fight against corruption more seriously, helping to raise economic growth to between 4 and 8 percent and earning the right to be taken seriously by donor countries.

Wolfowitz singled out an anti-corruption campaign in Nigeria for praise, said Ethiopia was engaged in a project with the World Bank to keep development assistance free from political interference and noted Rwanda had made enormous progress since a genocide in 1994.

"The two (states) that I think have the greatest potential ... are Ghana and Tanzania, big enough (to grow) ... but small enough that they don't have the challenges of the really big ones like Nigeria and Ethiopia," he said.

With African civil wars ending, the rise of multi-party politics and a new focus on good governance has helped convince international lenders of a climate deemed favorable to development.

While development statistics by which Africa is judged are still unfavorable, Wolfowitz said it was possible that states could get locked into a virtuous circle in which they copy each other's best practices.

The United States should respond to positive news in Africa by increasing its contribution to the International Development Association, the World Bank's main lending facility for its poorest borrowers, when donors meet next year, Wolfowitz said.

Washington's contributions to IDA has declined from 21.6 percent to 13.8 percent of total contributions, he said.

"There's a need for more and there's a need for the United States to do more .... I'm hopeful and I plan to come to some more American cities so that we can get that kind of support."

"I don't think I need to persuade this group that fighting global poverty is a moral responsibility for a global player like the United States," he said.

Wolfowitz, a key advocate of the Iraq war while he was deputy U.S. defense secretary under Donald Rumsfeld, said he could not comment on the war in his capacity as World Bank chief.

His speech at a synagogue on Sunday was interrupted by Iraq war protesters, and a few graduate students at a round table discussion with former Mayor Andrew Young at Georgia State University on Monday attempted to spark debate on the subject.