Afghanistan's elections officials have ordered a recount of ballots in some 500 polling stations.
Noor Muhammad Noor, a spokesman for the Independent Election Commission, told reporters on April 19 the recount will place in polling stations where officials suspect electoral fraud may have taken place.
Noor did not give any further details.
More than 7 million of Afghanistan's 12 million eligible voters cast their ballots in the April 5 presidential and provincial councils elections, despite threats by Taliban militants.
Preliminary results are due April 24.
Partial results released on April 13 showed former Foreign Minister Abdullah Abdullah in the lead, while former Finance Minister Ashraf Ghani came in second.
Officials warned that the front-runner could easily change as the vote count continues.
The winner will succeed outgoing President Hamid Karzai in the first democratic transition of power in Afghanistan.