KABUL, Afghanistan -- Afghanistan's election commission delayed a planned release of full results from the April 5 presidential election to allow for recounts and audits, officials said Wednesday, a development that adds to the confusion surrounding the balloting to replace President Hamid Karzai.

The results were expected on Thursday, but Independent Election Commission director Ziaulhaq Amarkhil said in a statement they would be postponed until at least Saturday to ensure they are not tainted by fraud.

"The commission is responsible to the Afghan electorate," said Amarkhil.

The winner will replace Karzai, who is ineligible for a third term, and oversee a tumultuous period as the U.S. and NATO are expected to withdraw most of their troops from the country by the end of this year, leaving Afghan forces to fight the fierce Taliban insurgency on their own.

Karzai, whose relations with Washington have sharply deteriorated, is the only president the country has known since the 2001 U.S.-led invasion ousted the Taliban.

The full results, now expected on Saturday, will still be preliminary and must be further investigated by a separate Election Complaints Commission before final results are to be announced May 14.

So far, partial results of about half the 7 million votes cast show former foreign minister Abdullah Abdullah in the lead with 44.5 per cent of the votes tallied and ex-finance minister Asraf Ghani Ahmadzai in second place with 33.2 per cent.

After yet more ballots are tallied, another batch of partial results are to be released on Thursday, said IEC spokesman Noor Mohammad Noor in a televised press conference Wednesday.

It's unclear if either Abdullah or Ahmadzai would secure a majority to avoid a runoff. Each insists he would pass the 50-per cent mark once all the votes are counted and fraudulent votes discounted.

If neither candidate gains a majority, a runoff would need to be held in late May or early June, meaning it could be several more weeks before a winner is declared.

Nearly three weeks after the voting, it's still unclear how many ballots might be invalidated in fraud investigations, in part because each commission is doing their own auditing.

The IEC has said more than 1,000 polling stations are being audited or recounted, which could potentially affect hundreds of thousands of votes, but it's unknown if the separate complaints commission might question more ballots.