Kabul, Reuters—Afghan presidential candidate Abdullah Abdullah withdrew observers from a UN-supervised audit of votes on Wednesday, a member of his team said, after threatening to pull out of an agreement to resolve a deadlocked election.

The audit of ballots from a June run-off vote is part of a US-brokered deal between Abdullah and Ashraf Ghani, both of whom say they won the election that was hoped would usher in Afghanistan’s first democratic transfer of power.

“We boycotted the audit process today because it is worthless for us. Let them carry on,” Fazel Ahmad Manawi, Abdullah’s chief auditor, told Reuters.

US Secretary of State John Kerry has twice flown to Afghanistan since the June 14 vote to defuse tension and push the rivals to agree to cooperate.

US officials stepped in again on Wednesday and were holding emergency talks with Abdullah, according to a member of his team.

The crisis over the outcome of the vote has raised the specter of instability, turmoil and perhaps even another round of fighting in a country already battling a potent Taliban insurgency.

Former finance minister Ghani is a member of Afghanistan’s biggest ethnic group, the Pashtuns, who make up of most the population in the south and east.

Abdullah, a former foreign minister, has strong support from minority Tajiks.

Ethnic Tajiks are largely based in the north of the country and made up the bulk of Northern Alliance fighters who battled the Taliban and assumed top jobs in the US-backed government that replaced the Taliban after their ouster in 2001.

Abdullah won a first round vote in May but without a majority needed for outright victory, preliminary figures showed.

Ghani won the run-off by a margin of more than a million votes but Abdullah complained of rigging and demanded a recount in which fraudulent votes would be thrown out.

Abdullah’s team believe that the more fraudulent votes are thrown out, the better his chances will be of victory but they have complained that the rules of the audit are not strict enough to weed out the illegitimate ballots.

A UN spokesman confirmed there had been a “temporary disruption” to the audit but declined to elaborate.

On Tuesday, Abdullah’s team said the United Nations had until Wednesday to accept its demands to tighten the rules for identifying and discarding ballots deemed fraudulent.

That would invalidate 1.5 million votes most of them for Ghani, they say, putting Abdullah in the lead.

The crisis comes at a time of deep 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.

Outgoing President Hamid Karzai, who is not allowed by the constitution to run again, has urged both candidates to respect the terms of the US-brokered deal.

It is not clear how developments would play out if Abdullah were to reject the recount but the United Nations has said the audit would go on regardless and it is likely Ghani would eventually be confirmed as president.

A member of Abdullah’s team said he would not recognize a government to merge from what he sees as an unfair election.