Afghanistan's Independent Election Commission says presidential candidates should wait for official results before declaring victory in Thursday's vote.
Both top candidates -- incumbent President Hamid Karzai and former Foreign Minister Abdullah Abdullah -- say they have enough votes to win without a runoff.
But preliminary results are not expected until early next week. An election commission official, Zekria Barakzai, says it is the job of his organization to release the results. A U.S.-funded observer mission says the election has been "credible."
But the International Republican Institute also says there are reports of serious irregularities. Election officials say there are reports of ballot-stuffing and faulty voting equipment.
U.S. President Barack Obama congratulated Afghans on Friday for voting despite threats from extremists. Mr. Obama said the election is an "important step forward."