KABUL, Afghanistan - France's foreign minister urged Afghanistan's political rivals Sunday to accept the findings of a fraud investigation that could force a runoff vote in the country's disputed presidential election.

The Aug. 20 vote was marred by charges of ballot-stuffing and voter coercion, mostly to President Hamid Karzai's benefit. Enough of Karzai's votes are suspect that voided ballots could drop him below the 50 per cent threshold needed to avoid a runoff.

A UN-backed panel investigating fraud claims was due to issue findings last week, but the announcement has been repeatedly delayed.

As reports made a runoff sound increasingly likely, a flurry of diplomats and dignitaries have called or visited Karzai. People familiar with the talks said they pressed Karzai to accept rulings mandating a runoff, but that the president refused to make any such commitment until the fraud decisions were announced.

Top challenger Abdullah Abdullah has said he has faith in the process, but he also will wait to see the figures before commenting.

"For the moment we are worried ... because it seems that not everybody is ready to accept the results," French Foreign Minister Bernard Kouchner told reporters in Kabul. "They must accept the results."

Both Karzai and Abdullah say they expect the panel to rule in their favour. Karzai, who has more than 54 per cent in preliminary results, says there will be no second round; Abdullah says there definitely will be.

Asked why the candidates should commit to the findings before knowing what they are, Kouchner said both sides "have to sacrifice ... we need a consensus."

"At the end of the day, a government is necessary," Kouchner said.

The fraud panel's rulings have been delayed by two days of discussions with Afghan election officials to clarify the methods used to decide which votes were fraudulent, according to several people familiar with the meetings. They spoke on condition of anonymity because of the sensitivity of the talks.

The prolonged debate raises questions about the willingness of the Independent Election Commission, whose officers are appointed by Karzai, to accept a result that will reportedly require a runoff.

Afghan law declares the UN-dominated Electoral Complaints Commission the final arbiter on fraud allegations. However, members of the Independent Election Commission, which has the authority to order a runoff, have argued that some of the investigations are outside the normal complaint process and that the fraud panel does not have the final say.

Karzai's camp denies it is trying to influence the result.

"There is no way we can influence them, and even if we can, we are not going to do it," campaign spokesman Waheed Omar said.

International pressure is mounting on the rivals to find a way out of the deepening political impasse, which threatens the legitimacy of the Afghan government and the future of the U.S.-led military mission in the insurgent-wracked country.

A second round of balloting would have to be held before winter, which traditionally begins in mid-November. Once heavy snows block mountain passes, a runoff would have to wait until spring, leaving the country in political limbo for months as the Taliban gains strength.

The U.S. effort is already troubled by a spike in deaths that has damaged public support for the war at home. In the latest violence, an American service member was killed by a bomb attack in the south Sunday, the military reported.

Fearing the political crisis will worsen, UN Secretary-General Ban Ki-moon, U.S. Secretary of State Hillary Rodham Clinton and British Prime Minister Gordon Brown telephoned both Karzai and Abdullah in recent days to express concern.

U.S. Sen. John Kerry, chairman of the Senate Foreign Relations Committee, and former U.S. ambassador to Afghanistan, Zalmay Khalilzad, are all in Kabul for talks with Afghan leaders.

In taped interviews to U.S. networks, Kerry said that a decision on whether to send more U.S. troops to Afghanistan could not be made before the election crisis is resolved.

"I don't see how President Obama can make a decision about the committing of our additional forces or even the further fulfilment of our mission that's here today without an adequate government in place or knowledge about what that government's going to be," he told CBS.

Though larger military decisions may be on hold, fighting continues.

Afghan and international forces raided a number of militant compounds in the south and east in recent days, killing more than 10 militants in firefights, said Capt. Staci Reidinger, a spokeswoman with U.S. forces.