Afghan President Hamid Karzai's charge that foreign powers are responsible for the country's election fraud is "preposterous," a U.S. State Department spokesman said on Friday.

"Suggestion that somehow the international community was responsible for irregularities in the recent election is preposterous," said State Department spokesman P.J. Crowley at a press briefing, rejecting Karzai's allegations.

"We're troubled by the comments that he made yesterday. From our standpoint, we are investing substantial resources to defeat al-Qaeda. It's in our interest, but in doing so we're also creating significant opportunities for the Afghan people," he added.

Crowley also confirmed that U.S. Ambassador to Afghanistan Karl Eikenberry had met with Karzai on Friday to seek clarification on his remarks.

Karzai on Thursday voiced accusations about fraud in the Afghan election, blaming it on foreign powers. He also said the West wants to see him weak, although he did not specifically mention the United States.

Earlier on Friday, the White House said Karzai's remarks were " troubling" and the U.S. is seeking his clarification.

"Obviously some of the comments of President Karzai are troubling. They're cause for real and genuine concern," White House spokesman Robert Gibbs told reporters.

U.S. President Barack Obama's recent sudden visit to Afghanistan is widely seen as aimed to pressure Karzai to make serious efforts to rein in corruption in the country.