Afghan President Hamid Karzai remains on track to be re-elected after the first round of voting, with ballots from 95% of polling stations counted.
The latest preliminary results released by the Election Commission give him 54%of the vote - above the threshold of 50% required to avoid a run-off.
His nearest rival, former foreign minister Abdullah Abdullah, is on 28%.
However, the Electoral Complaints Commission has begun investigating widespread allegations of fraud.
The election commission said it had quarantined ballots from another 2.15% of polling stations because of suspected irregularities.
The full preliminary result of the 20 August election had been expected 10 days ago but the fraud allegations have delayed the process.
The Election Complaints Commission ECC has said it found "clear and convincing evidence" of fraud.