Afghan presidential candidate Abdullah Abdullah will announce Sunday whether he will boycott next week's runoff against incumbent Hamid Karzai, his spokesperson said, after talks about how to resolve the country's ongoing election crisis appear to have broken down.

Abdullah spokesperson Fazel Sancharaki said despite reports to the contrary, Abdullah has not yet decided whether to remain in the Nov. 7 runoff and will decide late Saturday after he learns whether his demands are met.

He hopes to force the postponement of voting until the spring.

Abdullah had set out a number of conditions for the runoff in an effort to avoid the massive fraud that plagued the August election. The conditions included replacing Afghanistan's top election official, Azizullah Lodin, and suspending a number of ministers in Karzai's cabinet.

The proposals come after a UN-backed election commission found evidence of widespread fraud during the August vote and threw out hundreds of thousands of ballots cast for Karzai.

Abdullah will announce his decision Sunday morning, Sancharaki said.

Meanwhile, the Associated Press quoted two unnamed sources close to Abdullah, an Afghan and a Westerner, who said the challenger has already decided to boycott the runoff.

The Westerner said talks broke down Friday, which prompted Abdullah to decide to boycott the vote.

The Afghan said the decision came after a fruitless meeting with Karzai on Thursday during which the two discussed Abdullah's demands.

According to Afghan electoral law, votes cast for a candidate who formally withdraws from a vote will be disqualified.

However, a spokesperson for Afghanistan's election commission told the Associated Press that it is too late for Abdullah to officially withdraw.

According to Noor Mohammad Noor, if Abdullah's supporters simply choose to boycott the vote, it will still go ahead as scheduled.

"The election will be held and all procedures will go as normal," Noor said.

"I think (Abdullah dropping out) is the wrong decision," Nasir Islam, a professor of governance at the University of Ottawa, told CTV News Channel on Saturday afternoon.

"I think he probably knows on the one hand that he's probably not going to be elected. On the other hand, he is quite angry because he asked for a deal to be made before the runoff and he asked the president to drop three of his colleagues," but that did not happen.

Islam said a single candidate election would damage Karzai's image further.

"The Karzai government has already been traumatized by all the kinds of statements that have been given by corruption and election fraud and now of course Dr. Abdullah's departure," he said.

"The election will take place, even if there is a single candidate, but it will be a very curious situation and obviously it will erode the legitimacy of the Karzai government a little bit more,"

U.S. Secretary of State Hillary Clinton said the runoff's legitimacy would not be undermined by a boycott.

"We see that happen in our own country where, for whatever combination of reasons, one of the candidates decides not to go forward," Clinton told reporters in Abu Dhabi. "I don't think it has anything to do with the legitimacy of the election. It's a personal choice which may or may not be made."

However, a boycott would undermine the Afghan government's attempt to bolster its credibility after the August vote.

A strong and legitimate Afghan government is considered essential for the United States to consider further increasing its troop levels in the country.

President Barack Obama is currently meeting with his key advisers to evaluate his Afghan strategy.

"I think Barack Obama would have to work with the Karzai government and that's a problem because there are questions whether the Karzai government is a credible partner or not," said Islam.

With files from The Associated Press