WASHINGTON (AP) -- President Barack Obama has taken the unusual step of intervening in a foreign election, asking both candidates in Afghanistan's disputed presidential race to allow the process for investigating fraud claims to go forward and threatening a cutoff in U.S. aid if "extra-constitutional measures" are taken.
Obama called the leading candidate, Ashraf Ghani Ahmadzai, on Tuesday, the day after he spoke to Ghani's opponent, Abdullah Abdullah. The White House said Obama told both candidates that the U.S. expects fraud allegations to be thoroughly reviewed, urging the two men to seek a resolution that doesn't undermine Afghanistan's fragile national unity.
"He also noted that there is no justification for resorting to violent or extra-constitutional means, which would result in the end of U.S. assistance to Afghanistan," the White House said in a statement.
The firm warning appeared to be directed mostly at Abdullah, who told thousands of supporters on Tuesday that he will declare victory, amid calls from some of his supporters for Abdullah to form a "parallel government."
Abdullah claims massive electoral fraud is behind the preliminary results from a runoff vote that put him a million votes behind Ghani. He said Tuesday he doesn't accept the results of the fraudulent vote.
White House press secretary Josh Earnest said the process of judging the fraud allegations must be allowed to conclude.
"The preliminary results are not final or authoritative and may not predict the final outcome," he said.
It is unusual for a U.S. president to speak to foreign political candidates during an election, but Obama thought it was important to reach out given the seriousness of the situation and the U.S. interest in maintaining stability in Afghanistan, the White House said.
The Afghan Independent Election Commission released preliminary election results Monday showing Ahmadzai well in the lead but said no winner could be declared because millions of ballots were being audited for fraud. Ahmadzai had about 56 percent of the vote to Abdullah's 44 percent.
The results announced Monday marked a sharp turnaround from the first round of voting on April 5, when Abdullah garnered the most votes, with 46 percent to Ahmadzai's 31.6 percent. But Abdullah failed to win the majority needed to avoid last month's runoff.
Abdullah has refused to accept any second-round results until all fraudulent ballots are invalidated.
NATO Secretary-General Anders Fogh Rasmussen said Tuesday that the fraud allegations were concerning. He urged both sides to work with Afghanistan's electoral authorities "to find a solution that ensures a credible outcome of the presidential election."
Rasmussen commented after an Oval Office meeting with Obama during which they discussed planning for an upcoming NATO summit in Wales in September, along with Ukraine and Afghanistan, among other topics. It was Rasmussen's final visit to the White House before he steps down later this year as head of the international military alliance.
Follow Darlene Superville on Twitter: http://www.twitter.com/dsupervilleap
Copyright 2014 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.