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

A UN-backed fraud panel is expected to decide this week whether to throw out enough votes to require a runoff between Karzai and his top challenger, Abdullah Abdullah. Doubts about the UN's neutrality could throw the panel's rulings into question.

It is a setback to hopes of the Obama administration and its international partners that the vote - the first presidential election run by Afghans - would restore legitimacy to a government plagued by weakness and corruption.

Karzai told a news conference that "confusion" over election results had been "created by Western elements in our country." He did not elaborate.

At a separate news conference, Eide said Galbraith's allegations were untrue in some cases and taken out of context in others. Eide was flanked by ambassadors from the United States, Britain and France in a show of international support for the UN mission and its embattled leader.

Final results have been delayed by more than a month as a UN-backed panel set up as a check on the Afghan-appointed election commission examines complaints and suspicious votes. Though preliminary tallies show Karzai winning with about 54 percent, enough Karzai ballots are suspect that the voiding of fraudulent votes could drop him below the 50 percent threshold needed to avoid a runoff.

Last week, Galbraith said he was sticking by his allegations and said the election fraud had been "preventable."

Among other things, Galbraith complained that polling stations were allowed to open in areas that were insecure, raising the likelihood of fraud. Eide said military operations were launched in a bid to secure to open as many stations as possible so Afghans in those areas had the opportunity to vote.

Once the election results become clear, President Barack Obama is expected to complete a review of Afghan strategy and decide whether to accept a recommendation by his top commander here, Gen. Stanley McChrystal, for up to 40,000 more troops.

Among the options under review is a plan to maintain US troop numbers at their current levels and shift the focus to missile strikes and special operations against al-Qaida leaders, including those sheltering in neighboring Pakistan.