Kabul: Afghan officials opened an investigation on Monday after front-running presidential candidate Abdullah Abdullah made fraud claims that could threaten a smooth transition of power during a pivotal year.
Abdullah demanded the sacking of Zia-ul-Haq Amarkhail, head of the Independent Election Commission (IEC) secretariat, over an alleged attempt by Amarkhail to remove unused ballots from the IEC headquarters on polling day.
Abdullah also said the IEC's turnout figure of seven million voters in Saturday's run-off election was probably false.
The allegations put former foreign minister Abdullah in direct conflict with election authorities as counting got underway after the second-round vote pitting him against ex-World Bank economist Ashraf Ghani.
The dispute erupted despite a plea from the United Nations for the candidates to give officials time to conduct the count and adjudicate on fraud complaints.
A successful election is seen as the key test of the 13-year international military and aid effort in Afghanistan as the bulk of US-led troops withdraw by the end of the year.
The interior ministry said a joint investigation with the IEC had been opened into the allegations, but the move was unlikely to satisfy Abdullah.
"The findings will come out soon," interior ministry spokesman Seddiq Seddiqi told the 1TV news channel.
Abdullah believes massive fraud denied him victory in the 2009 presidential race, and he has often said that only a repeat of ballot-rigging could stop him from winning this time.
"There is no collaborating evidence (of the turnout figure) at all throughout the country -- that is something that is questionable and what we are concerned about is once again engineered fraud," Abdullah told reporters late Sunday.
"The head of the secretariat was... caught red-handed and we want an investigation. We want him to be removed from his position."
Prolonged vote count
Counting the ballot will take weeks. The preliminary result is due on July 2, before the official complaints period begins, and the final result is scheduled for July 22.
The two candidates went through to the run-off after coming top in the eight-man first round race on April 5, when Abdullah secured 45 percent and Ghani scored 31.6 percent.
The Electoral Complaints Commission had registered about 560 complaints by Monday morning, including claims against both campaign teams, IEC staff and the security forces.
Amarkhail was stopped by police as he left the IEC head office in Kabul in a convoy of vehicles loaded with unused ballots, in an alleged breach of electoral procedures.
Saturday's election was hailed a success despite more than 50 people killed in separate Taliban strikes on polling day.
The deaths included five election workers killed when their bus was hit by a roadside bomb in Samangan province, and five members of one family who died when a Taliban rocket hit a house near a polling station.
Eleven voters in the western province of Herat had their fingers -- which were dipped in ink to register their ballot -- cut off by insurgents.
The White House praised voters' courage and called the elections "a significant step forward on Afghanistan's democratic path".
The Taliban had threatened to kill voters and officials, saying the election was an American plot to control who governed Afghanistan.
All NATO combat forces are due to withdraw from the country by December, though 10,000 US troops will remain into next year.
President Hamid Karzai, who has ruled since the fall of Taliban in 2001, was constitutionally barred from standing for a third term.
On the campaign trail, both candidates offered similar pledges to tackle rampant corruption, build much-needed infrastructure and protect citizens from violence.
Priorities for the incoming president will be to stabilise the faltering economy as aid falls, and a fresh attempt to bring peace after decade