The Electoral Complaints Commission (ECC) published the findings of its long-awaited investigation into poll fraud in Afganistan's elections on Monday.
The report, published on the ECC's website, called for ballots cast at 210 polling stations during the country's August 20 polls to be discarded.
Sources told Al Jazeera that the move had pushed Karzai's share of the vote to below 50 per cent, the number needed to avoid a runoff with Abdullah Abdullah, his main rival.
"Diplomatic sources tell me that the figures clearly show Hamid Karzai is well below the crucial 50 per cent margin," James Bays, Al Jazeera's correspondent in Kabul, reported.
"I understand that key ambassadors are now meeting with the UN to discuss what is the next step, what is the way forward now that Hamid Karzai hasn't reached the 50 per cent following this procedure by the Electoral Complaints Commission."
Fazel Sancharaki, Abdullah's campaign spokesman, welcomed the ECC's findings, saying: "This is a step forward."But Waheed Omar, a spokesman for Karzai's campaign, dismissed claims that the ECC report meant a runoff would be necessary.
"I do not know how any diplomatic source can come out with a result out of what has been said today," he told Al Jazeera.
"We will keep our reaction reserved for when the final, certified results of the elections are annocuned [by the Independent Election Commission] and that will be legally binding for us."
Source: Al Jazeera (English)