Afghanistan’s opposition leader Dr Abdullah Abdullah warned yesterday that he might not be able to restrain angry supporters from taking to the streets as it emerged that more than one in five votes cast in last month’s election were fraudulent.

“I have urged them strongly not to do that,” he told The Sunday Times as his followers called for demonstrations. “They are aware of the fragility of the situation.”

He added: “If you are asking for a guarantee, 100%, will you be able to control everyone in this country, the answer is no, n ... o.”

Even before the August 20 poll, Abdullah’s supporters were predicting Iran-style protests “with Kalashnikovs” if President Hamid Karzai won in the first round, insisting he could do so only by cheating.

With 92.8% of ballots counted, Karzai is ahead with 54.3% of the vote, enough to avoid a second-round run-off if confirmed when the count is completed. It is remarkably close to the 55% he secured in the 2004 election, although there is widespread disillusionment with his government.

The Election Complaints Commission, sponsored by the United Nations, has been swamped by allegations of vote rigging at 2,804 polling stations. There are claims of police intimidation, bribery and ballot-box stuffing. At least 726 of the allegations are deemed serious enough to sway the outcome and the inquiry could take months.

Abdullah, who is in second place with 28.1% of the vote, insisted that the only fair outcome would be a second round of voting.

“We’re talking about big, big fraud,” he said.

The international community is desperate to encourage Karzai and his two main challengers to form a national unity government and avert violent protests.

The Sunday Times has obtained a report by monitors from the Office for Democratic Institutions and Human Rights, completed yesterday, which said 1,253,806 votes — 23% of the total counted so far — could be fraudulent.

According to the analysis, if all these votes were cancelled then Abdullah’s share would increase by almost 4 percentage points to 32.03%. Karzai’s share would drop by 6.62 points to 47.48%, triggering a second round. The share of Ramazan Bashardost, the third-placed candidate, would rise to 10.7%.

The scale of the fraud is a huge embarrassment for western governments already facing questions from their own voters about soldiers’ deaths in Afghanistan. Five American troops died yesterday.

Lieutenant-General Karl Eikenberry, the US ambassador, last week warned Karzai against declaring victory prematurely. But Richard Holbrooke, the US special envoy to the region, has ruled out a rerun.

UN officials point out that the prospect of a second round grows slimmer as the results are delayed, because the onset of winter means much of the country will soon be inaccessible.

It appears some of Holbrooke’s staff were initially involved in leaking the reports of election fraud, seeing it as a chance to clip Karzai’s wings. They believed that an unconvincing victory would give the West leverage to persuade the president not to dismiss reformist ministers and replace them with warlords with whom he had made electoral deals.

However, as the political tensions threaten to spiral out of control, Washington is now trying to play down the problem.

“It is an achievement elections went ahead at all,” said one US official last week.

Asked what legitimacy a future Karzai government would have, the official said: “We’re not there to support the Afghan government. We’re there to disrupt, dismantle and demolish Al-Qaeda.”

Within the British government there is considerable unease at the idea of sending soldiers to die on behalf of a fraudulently elected administration.

“We will not be party to any whitewash in respect of this election,” said David Miliband, the foreign secretary. “It is vital there is a credible result.”

Whitehall is pushing for a unity government as the only way out. One Foreign Office official admitted that neither Karzai nor Abdullah was “making the right noises”, however.

Karzai officials claim that Abdullah has asked for 12 ministries as the price of his support, but yesterday he denied that he was about to make a deal.

“I will not surrender to fraud,” he said. “A coalition with a fraudulent regime? I won’t find myself in such a system. Those who voted for me wanted change.”

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