The United Nations has admitted for the first time there was widespread fraud in Afghanistan's presidential election in August.
An Electoral Complaints Commission has already found "clear and convincing evidence of fraud".
The head of the UN mission in Kabul, Kai Eide, said on Sunday there was significant fraud in polling stations in the south and the south-east during the presidential election on 20 August.
Mr Eide said he did not help cover-up the fraud and he still believes a result can still be reached that Afghans would find credible.
Mr Eide's former deputy Peter Galbraith has been sacked after accusing him of covering up the extent of the fraud.
Mr Eide said on Sunday that the accusations were false and undermined the election process.
A final result from the election is expected within days. According to EU election observers, about 1.5 million votes - about a quarter of all ballots - could be fraudulent.
The Electoral Complaints Commission and the Independent Election Commission have almost completed an investigation of ballot boxes identified as suspicious.
Karzai still leads
The BBC reports President Hamid Karzai leads preliminary results with about 55% of the vote, considerably ahead of his nearest rival Abdullah Abdullah, who has 28%.