Election commission to open 155 more stations despites fears over fraud and security.
He also demanded the suspension of four ministers who campaigned for Karzai.
Abdullah’s camp had set a deadline of Saturday for Karzai to bow to his demands and supporters say that he will not take part in a contest that will not be free and fair.
But the demands have been virtually ignored, with the IEC saying Ludin can only be dismissed by the supreme court while Karzai says Abdullah has no right to interfere in ministerial positions.
Asked what Abdullah’s stance would be if his conditions were not met, an MP involved in his campaign said the candidate would not take part in the runoff.
“If our conditions are not met and an election takes place on November 7, that will not be an election but a fraud trap,” Ahmad Bezad told the AFP news agency.
Al Jazeera’s Jonah Hull, reporting from Kabul, said: “His [Abdullah’s] spokesman [says] that a final decision hasn’t yet been made by Dr Abdullah to react to the fact that many of those conditions have not been met.
“We’re now told [Abdullah] is in intensive meetings; he is still making up his mind.”
The Associated Press later quoted Satar Murad, the campaign manager, as saying Abdullah “as of now” planned to call for a boycott of the upcoming runoff, although he said Abdullah might still change his mind.
Abdullah is said to be keen to halt the runoff in order that it will be delayed until next spring.
Hillary Clinton, the US secretary of state, said that should Abdullah boycott the vote, the legitimacy of the elections would not be affected.
“I don’t think it has anything to do with the legitimacy of the election,” she said, in response to a question on the issue at a press conference in Israel.
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“We see that happen in our own country where, for whatever combination of reasons, one of the candidates decides not to go forward.”
The first round of Afghanistan’s elections on August 20 was so badly affected by ballot-box stuffing and distorted tallies that more than one million votes were thrown out.
The fraud pushed Hamid Karzai, the president, below the required 50 per cent margin needed to win, forcing the country into a second round to be held on November 7.
Abdullah has accused the country’s electoral commission of being complicit in the fraud.
Abdullah’s conditions for the runoff to take place included the dismissal of Azizullah Ludin, the government-appointed co-ordinator, to ensure a fair vote.
But both the Karzai campaign and the election commission have said that Ludin will not step down.
Our correspondent said Abdullah’s list of conditions included “stringent” demands involving both the government and the election body involved in organising the polls.
“The only one of his conditions that has been met is a demand for more accredited observers from the Abdullah camp and they will give him 20,000 accreditations,” Hull said.
“But that is the only one and that is what puts him in a difficult position of deciding whether to participate given that his own minimum requirements have not been met.”
The growing uncertainty over Abdullah’s participation comes as the US president continues consultations on further troop deployments to Afghanistan.
Barack Obama reviewed his options with the joint chiefs of staff – which includes the service chiefs from the army, navy, air force and marines – in Washington on Friday, his seventh such meeting.
General Stanley McChrystal, the leader of US and Nato forces in Afghanistan, has requested 40,000 more troops, giving warning on the deteriorating situation in Afghanistan.
But the joint chiefs of staff did not make recommendations to Obama about troop levels, an unnamed senior administration official was quoted by the Associated Press as saying.
The Washington Post newspaper reported, quoting US officials, that Obama asked the commanders to provide him with more options for troop levels.
Some of the alternatives would allow Obama to send fewer new troops than the number sought by McChrystal, one official said.
Obama is expected to receive several options from the Pentagon about troop levels next week, according to the two officials.
Obama’s advisers have said, before he can determine troop levels, he must decide whether to embrace a strategy focused heavily on counterinsurgency, which would require additional forces to protect population centres, or one that makes counterterrorism the main focus of US efforts in the country, which would rely on relatively fewer American troops.