Partial results from last month's Afghan presidential election show Hamid Karzai inching toward re-election in a single round.

However, the election is close enough that investigations into fraud could play a decisive role in determining the outcome.

The latest returns, with 60% of polling stations tallied, give Mr Karzai 47.3% of the vote to 32.6% for his main opponent, former foreign minister Abdullah Abdullah.

Most of the polling stations yet to be tallied are in the south where Mr Karzai draws strong support, suggesting the result there could secure the majority needed to avoid a second round.

However, Mr Abdullah has accused the authorities of stuffing ballots on the president's behalf, especially in the south.

An Electoral Complaints Commission, an independent body headed by a Canadian and mainly appointed by the United Nations, is investigating more than 600 complaints it says could be serious enough to alter the outcome.

It can throw out suspicious ballots or even exclude results from entire districts.

Complete preliminary results are expected in the next few days.

Those results could then be changed by ECC.

If no candidate wins 50%, a second round run-off must be held, now set for 1 October.