KABUL, Afghanistan -- An audit of Afghanistan's disputed presidential election won't be finished until around Sept. 10, the United Nations said Thursday, quashing hopes the new president would be determined before a coming NATO summit.

The U.N. has been helping supervise an audit of 8 million ballots to see who will succeed President Hamid Karzai, with the goal that the new president would be inaugurated by the end of August. But the audit has become increasingly contentious, which has slowed the process.

The announcement by the U.N.'s representative in Afghanistan, Jan Kubis, came after a meeting with Karzai.

The U.N. said in a statement that Kubis told Karzai that "a rigorous and credible audit required time, but could be completed around 10 September. Following all necessary steps, as required by law, the inauguration of the new President should then be possible soon after."

The U.S., the international community and Karzai had wanted to see the new president sworn in before the summit so he could represent Afghanistan at the meeting, which is expected to discuss issues such as funding and support for Afghanistan's security forces.

Karzai's office has said previously that the Tuesday deadline was not extendable. The president's office said in its own statement Thursday that Kubis had informed the president that completing the audit by that date was "not possible."

Karzai has already notified NATO that he will not attend the conference scheduled for Thursday and Friday in Wales, said his spokesman Aimal Faizi.

Gen. Martin Dempsey, chairman of the U.S. Joint Chiefs of Staff, has said it would be disappointing if Afghan leaders don't settle their election dispute in time for the NATO summit.

If Afghanistan is unable to send any representative, "we'll have to work around the absence," Dempsey said during a quick stop in Kabul on Tuesday. He added that NATO leaders will still have "a very important discussion about how that commitment [to Afghanistan] evolves in the future."

Former Foreign Minister Abdullah Abdullah and former Finance Minister Ashraf Ghani Ahmadzai are both vying for the presidency in a contested race that has seen widespread allegations of fraud. Karzai is barred by law from running for a third term.

Abdullah won the first round but not by enough to avoid a June 14 runoff. Preliminary results from the runoff showed Ahmadzai ahead, which unleashed sharp cries of fraud from Abdullah's camp and fears that the election process could spiral into violence. Ahmadzai's supporters also have alleged fraud in the vote.

U.S. Secretary of State John Kerry, who has traveled twice to Afghanistan to try to bring both sides together, helped broker the audit as a way to determine the winner. The audit was to be supervised by representatives from both political camps.

But on Wednesday, Abdullah's camp pulled their observers from the process, saying their fraud concerns were being ignored. Ahmadzai's side later pulled out after a request from the United Nations to ensure fairness, and the audit -- which had been temporarily paused -- continued.

Information for this article was contributed by Amir Shah of The Associated Press.

A Section on 08/29/2014