A member of a U.N.-backed panel set up to investigate fraud complaints in Afghanistan's election resigned Monday, blaming what he called "the interference of foreigners" in a vote already mired in controversy.

The fraud panel is expected to decide this week whether to throw out enough votes to force a runoff between President Hamid Karzai and his top challenger, Abdullah Abdullah.

Maulavi Mustafa Barakzia was one of the only two Afghans on the Electoral Complaints Commission. He alleged Monday that the three foreigners on the panel -- one American, one Canadian and one Dutch -- were "making all decisions on their own" without consultation.

A day earlier, the top U.N. mission chief, Kai Eide, acknowledged "widespread fraud" had occurred in the Aug. 20 presidential election and said the complaints commission was working to decide the extent of it.

Eide was criticized by his deputy, Peter Galbraith, who had alleged that the U.N. mission chief played down 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.

The vote has been a setback to hopes of the Obama administration and its international partners. Many had hoped the first presidential election run by Afghans would restore legitimacy to a government plagued by weakness and corruption.

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

In the latest reported violence, the international coalition said its forces killed several militants Sunday in an exchange of fire with insurgents in southern Zabul province's Qalat district.

The NATO-led force said it launched another operation Sunday in another southern province, Helmand, detaining "several suspected militants linked to the narcotics industry" after insurgents attacked them with machine gun fire.

Helmand is a Taliban stronghold that produces about 70 percent of the opium in Afghanistan, which supplies the vast majority of the world's supply.