KABUL (Reuters) - One of two candidates competing to succeed Afghan leader Hamid Karzai threatened on Tuesday to pull out of a U.N.-backed audit of a disputed presidential election, undermining a process meant to defuse a volatile standoff between the contenders.
The investigation is part of a U.S.-brokered deal between presidential candidates Abdullah Abdullah and Ashraf Ghani, both of whom claim to have won the election that was hoped would usher in the country's first democratic transfer of power.
The crisis over the outcome of the vote has raised the spectre of another round of war in Afghanistan after the country was torn apart by years of fighting in the 1990s, which eventually led to the rise to power of the Taliban.
On Tuesday, Abdullah's team said the United Nations had until Wednesday to accept their demands to widen the criteria for identifying and discarding ballots deemed fraudulent from a June run-off vote.
"If our demands are not taken into account we will not recognise the legitimacy of the process," said Abdullah's spokesman, Mujib Rahman Rahimi.
Abdullah's supporters think that the more fraudulent votes are thrown out, the more likely he is to win.
Rahimi said if the audit went ahead without accepting Abdullah's demands his camp would not recognise any future government as legitimate - a dangerous prospect likely to deepen ethnic and political divisions in the fragile country.
Afghanistan was plunged into turmoil in April when Abdullah, a former foreign minister, led after a first-round vote but failed to secure an outright majority.
He trailed behind former finance minister Ghani in the June run-off, according to preliminary figures, and has since rejected the outcome, accusing Ghani's team of rigging the vote with Karzai's help - an accusation both Ghani and Karzai have rejected.
The crisis comes at a time of much anxiety in Afghanistan as the United States, Kabul's biggest aid donor, and other NATO nations withdraw their troops after nearly 13 years of fighting Taliban insurgents.
Interminable chaos as Western forces pull out would be a huge embarrassment for those countries which have spent billions of dollars and lost about 3,500 soldiers in a bid to bring peace and stability.
Karzai, who is not allowed by the constitution to run for the presidency again, has urged both candidates to respect the terms of the U.S.-brokered deal.
"President Karzai has started a series of meetings and consultations with both candidates," said his spokesman, Aimal Faizi.
"Tonight he is meeting with Abdullah Abdullah and Ashraf Ghani to ask them to cooperate with the political process."
Abdullah's refusal to accept the outcome of the vote threatens to split the country along ethnic lines and possibly setting the stage for more violence.
Afghan officials and diplomats worry there are too many powerful interests competing for power and they fear clashes between power-brokers could quickly escalate, although few expect any immediate outbreak of hostilities.
Western powers hope a new leader will be in place before Sept. 4, when a NATO summit is due to be held in Wales. Countries at the summit will weigh how much aid Afghanistan will get after most foreign troops pull out.
"God forbid," said one senior diplomat, commenting on the likelihood of conflict. "More negotiations, bargaining threats, but hopefully locals will find a solution."
Ghani's team played down the significance of the threat from Abdullah's representatives, saying it indicated Abdullah, who is expected to return from India on Tuesday, had poor control over his camp.
"Abdullah is out of the country and every time he is out of the country, the team make their own statements," said Ajmal Abidi, a spokesman.
Another source in Abdullah's camp said Abdullah himself was not against talks: "Abdullah still sees room for negotiation, but it is true he doesn't have much control over his own powerful men."
As part of a plan to end the crisis, the Independent Election Commission is meant to throw out, or "invalidate", ballots deemed fraudulent in an audit of all eight million votes cast.
"The invalidation process is just a joke and there is no intention of throwing out fraudulent votes," Fazel Ahmad Manawi, Abdullah's chief auditor, told reporters. "Whatever consequences are going to follow, we will not be responsible."
Writing by Jessica Donati; Editing by Maria Golovnina and Robert Birsel