The Afghan election headed for a second round run-off in mid-June between Abdullah Abdullah, a former opposition leader, and ex-World Bank economist Ashraf Ghani after final results on Thursday showed no candidate had won an absolute majority, Reuters reported.
The run-off will be held on June 14 and the results will be announced on July 22.
The winner will be taking over the presidency at a crucial time with most Western forces due withdraw from Afghanistan by the end of the year, the Taliban insurgency still raging, and an agreement with Washington for some U.S. forces to stay on hanging in the balance.
Abdullah, a former leader in the anti-Taliban Northern Alliance, scored 45 percent of the vote in the first round held on April 5, followed by Ghani with 31.6 percent, the Independent Election Commission (IEC) said.
"As the none of the candidates got more than 50 percent of the vote, the election goes to the second round," the commission's chief Ahmad Yousuf Nuristani told a news conference.
Former foreign minister Zalmai Rassoul, widely seen as incumbent President Hamid Karzai's favored candidate, finished a distant third with 11.4 percent, but has since joined Abdullah's camp.
Karzai was constitutionally barred from standing for a third term, having been first elected in 2004. He earlier held the presidency for two years on an interim basis after Afghan forces backed by the United States ousted the Taliban from power in late 2001.
Having served as foreign minister in the early years of Karzai's presidency, Abdullah ran against Karzai in a 2009 election, but pulled out of a run-off due to allegations of electoral fraud and has been a vocal critic of Karzai's administration ever since.
The run-off will be held two weeks later than initially planned, partly due to the loss of election materials that were destroyed by the Taliban in an attack on the IEC's headquarters ahead of the vote, Nuristani said.
Although the April 5 presidential election generated more complaints of serious fraud than in 2009, it is widely seen to have been a success because voter turnout was unexpectedly high and fewer votes were thrown out than last time.
Around 7 million of an eligible 12 million voters braved the threat of Taliban attacks to cast ballots in what will be the first democratic transition of power in their country's history.
The complaints commission said in its final report that a total 300,000 votes were cast out as fraudulent, compared to over a million in the previous election. Nuristani said some 3,000 election workers would be dismissed as a result of the complaints.