London  - Richard Holbrooke, the US special envoy to Afghanistan, urged critics of the country's presidential election not to "jump to conclusions."

In an interview with the BBC published late Thursday, Holbrooke said Afghanistan's Independent Election Commission (IEC) should be given time to complete the vote count.

He ruled out a re-run of the August 20 presidential polls, which have been marred by election fraud, as "not a viable option."

"Not all of the people in Afghanistan were able to vote, and as I've said many times before this election, there are imperfect elections throughout the west as well, and holding elections under these conditions is a very brave thing to do so let's see what happens before jumping to conclusions," Holbrooke said.

A UN-backed election complaints commission said earlier it was excluding votes from more than 70 polling stations, most of them in the south and east, due to convincing evidence of fraud in favour of te incumbent, President Hamid Karzai.

According to preliminary results from 92 per cent of polling stations, Karzai received 54.1 per cent of the vote, enough to avoid a run-off. His main challenger, former foreign minister Abdullah Abdullah, got only 28.3 per cent.

A European Union observer from Germany condemned Thursday what he called "really widespread fraud" in Afghanistan's presidential election.

Gunter Mulack pointed to implausibly high support at some voting stations for a single candidate, or ballot counts at some stations which exceeded the plausible number of voters.

Those considerations meant 700,000 of the nearly 5.5 million votes counted so far were of doubtful validity, he said.

British Foreign Secretary David Miliband said he was confident that a fair result could still be achieved.

Abdullah, who accused the IEC of favouring Karzai, ruled out cooperating with the president in a unity government. (dpa)