KABUL: UN-backed fraud investigators on Monday threw out nearly a third of President Hamid Karzai’s ballots from Afghanistan’s disputed August election, setting the stage for a runoff.

The rulings dropped Karzai’s votes to 48 percent of the total, below the 50 percent threshold needed for him to avoid a runoff with his top challenger, according to calculations by independent election monitors.

It was unclear, however, whether the Afghan-led Independent Election Commission (IEC) would accept the findings of the fraud panel and announce a runoff. Karzai’s spokesman said it was too soon to make a judgment based on the figures released by the panel.

That could mean a further delay in forming a new government that the US believes is needed to help combat the growing Taleban insurgency. A protracted crisis could also lead to political unrest.

The White House has also said no decision on sending more US troops to Afghanistan would be made before the election crisis is resolved — a stance reiterated by the civilian chief of the NATO military alliance on Monday.

An independent calculation by an election monitoring group, Democracy International, showed Karzai with 48.3 percent, or about 2.1 million votes, after more than 995,000 of his votes were thrown out for fraud. Overall, about 1.3 million votes of the more than 5 million ballots cast were voided. Abdullah Abdullah lost more than 201,000 votes, but his percentage rose to 31.5 percent from 27.8 percent previously.

Abdullah Abdullah campaign spokesman Fazel Sancharaki welcomed the fraud panel’s findings and said they showed Karzai’s percentage of the vote was 48 percent. “This is a step forward, now it is up to the IEC to announce the final results,” Sancharaki said. He said it would be illegal for the IEC to reject the fraud panel’s findings.

Karzai campaign spokesman Waheed Omar said, “I don’t think we can make any judgment based on the figures announced today.” Investigators only released raw data from their findings, but it was clear that hundreds of thousands of Karzai votes were voided. Karzai pledged to “fully respect the constitutional order,” a UN spokeswoman said.

In a telephone talk UN chief Ban Ki-moon urged Karzai “to respect the constitutional process and he was pleased to hear that the president says he will fully respect the constitutional order,” UN spokeswoman Michele Montas said.

“No one underestimates the challenges, there are security challenges, there are weather challenges,” Montas said, adding the UN was prepared to help organize a runoff if needed.

Grant Kippen, chairman of the Electoral Complaints Commission (ECC), said he did not see any legal way for the IEC to reject the results.

“Our decisions, our orders, are final and binding according to the law,” Kippen said. “We’ve followed the law very clearly, very precisely. My sense is that the IEC is going to follow the law as well.”

The White House on Monday prodded Afghanistan’s leadership to prove to their people and to the watching world that the results are legitimate.

White House press secretary Robert Gibbs said he would not get ahead of the election review process, but he pointedly framed some expectations.

“It’s going to be incredibly important for the world to see that Afghan leaders are willing to make this process legitimate, and that’s the process that we’re encouraging,” Gibbs told reporters.