A top adviser to World Bank President Paul Wolfowitz is leaving the institution, citing the continuing controversy surrounding Wolfowitz' handling of a pay package for his girlfriend.

"Given the current environment surrounding the leadership of the World Bank Group, it is very difficult to be effective in helping to advance the mission of the institution. Therefore, I have decided to leave for other opportunities," Kevin Kellems told The Associated Press on Monday.

Wolfowitz had tapped Kellems, who came from the White House and worked with him previously at the Defense Department, to become his adviser at the poverty-fighting institution. Kellems' arrival in June 2005 eventually touched off criticism among staff that Wolfowitz was sealing himself off with a small cadre of trusted advisers.

A special bank panel looking into Wolfowitz' handling of the 2005 promotion and pay raises for bank employee Shaha Riza is also believed to be examining other employment arrangements, including the one involving Kellems.

Kellems and another close Wolfowitz adviser, Robin Cleveland, each are paid more than $200,000 a year — compensation that has irked some bank staff. Critics say the lacked extensive development experience.

Kellems' last day is expected to be next week. He didn't say what he will do after leaving the bank.