Abdullah Abdullah, Afghanistan President Hamid Karzai's top challenger in the presidential election, has agreed to a run-off vote. (Jerry Harmer/Associated Press)

Afghan President Hamid Karzai's chief political rival, Abdullah Abdullah, has agreed to take part in the Nov. 7 run-off election and is predicting a higher turnout than in the previous vote.

"Our main focus is on the run-off in the pursuit of our agenda of change for this country," Abdullah, the country's former foreign minister, told CBC in an interview Wednesday from Kabul.

"In the second round, it will restore the faith of the people in the process" and likely lead to a higher voter turnout, he said.

Abdullah's comment came one day after Karzai bowed to international pressure and agreed to a run-off.

The original vote count from the Aug. 20 election gave Karzai 54.6 per cent of the total, enough to win outright against Abdullah.

But the United Nations-backed Electoral Complaints Commission found evidence of massive fraud during the election, and invalidated ballots from thousands of polling stations. Following those findings, Afghanistan's Independent Election Commission determined on Tuesday that Karzai did not earn enough valid votes for a majority.

Hundreds of thousands of ballots, including about 200,000 for Abdullah. were discounted because of fraud.

"On the issue of fraud, there are certain recommendations we will put forward [to the commission] for more transparent elections," Abdullah told CBC, although he declined to provide details.

"Hopefully we will have a more cleaner election…. No one will do a favour to the people of Afghanistan" [by perpetuating electoral fraud], he said.

In Ottawa, Afghanistan's ambassador to Canada, Jawed Ludin, told reporters Wednesday that the country is determined to make this second election a success without fault, but he acknowledged it won't be easy.

He urged the international community, particularly media, to support the effort, saying the process may not be up to Western standards, but it is the best Afghanistan can do.

"It's an understatement to say that it's a challenge to face. Yet there is absolutely no alternative," said Ludin, adding a coalition government would be illegal.

"The stakes are simply very high… for Afghanistan's future, but it's also high for the engagement that Canada has in Afghanistan and for the common objective that we have which is to contribute to the security of the world by the fight we are fighting against terrorism and extremism."

Some observers fear a second round of voting could lead to flare-ups of violence in a country already waging war with Taliban insurgents in many of its regions.

Run-off a 'huge challenge': UN's Ban

There is international concern that it would be difficult to muster the resources to prevent the kind of widespread voter fraud that occurred during the August vote.

UN Secretary General Ban Ki-moon said Tuesday that organizing a second election would be a "huge challenge," but the UN would do everything it could to make sure the election was transparent and credible.

Holding the vote in the cold season poses challenges in remote regions of the country, both for transporting ballots and drawing voters.

Legitimacy questioned

Karzai's decision to agree to a run-off vote was a relief to officials from Canada and the United States, who had both expressed concern about backing a government lacking in legitimacy.

Prime Minister Stephen Harper said that although the first round of elections was not without controversy, his government was pleased both candidates recognized the "need for a run-off election in the best interests of Afghan democracy."

U.S. President Barack Obama called Karzai's acceptance of the findings of Afghanistan's Independent Election Commission a key step in "a credible process" for the people of Afghanistan.

If the second round occurs without major issues, it's unclear whether a win for Karzai, still considered the favourite, would undo the damage to his reputation after the first round of voting.

Canadian Grant Kippen of Ottawa, who headed the UN commission, said Monday that investigators found a significant amount of fraud in the results sample they looked at.

The report confirmed that fraud occurred at more than 3,000 polling stations and all the ballots at 210 of those stations were ordered invalidated. Some voting stations showed fraud in up to 96 per cent of the ballots, according to the commission's report.

With files from The Associated Press