The top U.N. official in Afghanistan on Sunday acknowledged "widespread fraud" in the disputed presidential election and rejected allegations from a former deputy that he covered up cheating to smooth the path to victory for President Hamid Karzai.

The remarks by Norwegian diplomat Kai Eide appeared designed to win back respect for both the troubled U.N. mission and the entire election process ahead of a ruling by investigators on whether fraud was extensive enough in the Aug. 20 balloting to require a runoff.

Eide's reputation was tarnished when his deputy Peter Galbraith alleged that the U.N. mission chief downplayed allegations of widespread ballot-stuffing by Karzai's supporters. Galbraith, the top-ranking American in the U.N. mission, was fired Sept. 30 by U.N. Secretary-General Ban Ki-moon after the widely publicized dispute.