Hamid Karzai's rival refuses to take part in run-off

President Hamid Karzai's rival in the second round of the Afghan presidential poll says he will announce on Sunday whether he intends to quit the race.

Abdullah Abdullah called for the resignation of key election officials and others as a way to mitigate fraud and corruption in the vote.

But those demands were rejected earlier in the week in talks with Mr Karzai.

A senior adviser said that in talks on Friday, Mr Abdullah's team decided he should not take part in the poll.

But Mr Adbullah's campaign said on Saturday that no final decision had been made, and that the former foreign minister would announce his next move on Sunday.  

The BBC's Ian Pannell in Kabul says that if he withdraws it will raise serious questions about the credibility of the election.

However, US Secretary of State Hillary Clinton said a runoff with only one candidate would not necessarily threaten the legitimacy of the process.

"We see that happen in our own country where, for whatever combination of reasons, one of the candidates decides not to go forward," Mrs Clinton told reporters in the United Arab Emirates.