Afghan presidential candidate Abdullah Abdullah has preemptively rejected the results of last month’s election, set to be officially released Monday, saying the country’s electoral commission was involved in widespread fraud that tarnished the legitimacy of the runoff vote.

“Unless the clean votes are separated from those that are fraudulent, we will not accept the election results,” Abdullah said in a televised news conference Sunday night.

“We will refer to the people” on how to respond to Monday’s announcement, he said.

The stakes are high for a peaceful transfer of power, which would mark the first since the U.S. invasion of Afghanistan in 2001. The fragile government here continues to battle a nationwide Taliban insurgency as foreign troops prepare to withdraw by the end of the year.

Abdullah’s statement comes amid heightened concerns that the election outcome could plunge Afghanistan into further violence, possibly along ethnic lines. Abdullah, a former foreign minister who fought against Soviet forces, is of Tajik and Pashtun ethnicity. But he has been more associated with his mother’s Tajik heritage, and Tajik communities have shored up support for his candidacy. His rival, former finance minister Ashraf Ghani, is a Pashtun who commands widespread support among the Pashtun populations in the country’s southern and eastern regions.

Abdullah’s campaign has called for a far-reaching recount of votes in several provinces where Ghani’s support is strong and where it says election officials rigged ballot boxes in favor of Ghani. Two weeks ago, Abdullah played recorded telephone conversations allegedly of Ziaulhaq Amarkhil, the country’s chief election officer, encouraging election officials to support Ghani and possibly encouraging ballot stuffing. The authenticity of the recordings could not be verified. Amarkhil denied wrongdoing but resigned “for the good of the country.”

Abdullah says releasing results, which according to leaked figures show Ghani in the lead, before fraudulent votes are removed from the tally is dangerous and will mislead the country.

The Independent Electoral Commission has agreed to audit 1,930 boxes where tallies showed voter turnout at 100 percent. Ghani — who trailed Abdullah after the first round in April but now stands to win — says his campaign engaged in grass-roots mobilization that got voters out in even the most violent and isolated districts.

“One thing is clear: The level of fraud is very high,” said senior Abdullah adviser Mahmoud Saikal. For that reason, “tomorrow’s announcement does not mean much to us,” he said. “We will pursue what we want to pursue and differentiate between the clean and fraudulent votes.”

Saikal said representatives from both campaigns met Sunday. He said that no political deals were on the table and that discussions focused on initiating a more comprehensive recount.

“Neither side can form a strong government unless they share power with the other,” said Khalil Roman, a Kabul-based political analyst and former deputy chief of staff to President Hamid Karzai. “Afghanistan is facing tremendous internal and external threats. They have to form a coalition in order to face these threats.”

Sayed Salahuddin and Mohammad Sharif contributed to this report.