A roadside bomb has hit a vehicle carrying full ballot boxes in northern Afghanistan, killing three people a day after the country voted for a successor to President Hamid Karzai.
Eight boxes of votes were destroyed in the blast, which came as the three leading candidates voiced concerns about possible fraud.
Around seven million people turned out to vote, according to the Independent Election Commission (IEC), a turnout of over 50 percent despite poor weather and Taliban threats to target the election.
Sayed Sarwar Hossaini, police spokesman for the province of Kunduz, said the truck was hit as it carried ballot boxes from polling stations to Kunduz city.
"The blast killed three people, including an IEC member, a policeman and a driver. The truck and eight ballot boxes were destroyed," Hossaini said.
Amir Amza Ahmadzai, the head of the election commission in Kunduz, confirmed the incident.
Roadside bombs have been a key weapon for the Taliban in the bloody insurgency they have waged against Karzai's government and its Western backers since being ousted from power in 2001.
The attack followed a generally peaceful elections on Saturday, which was praised by the international community as a success.
Afghans have been praised for defying Taliban threats and turning out in their millions to vote in crucial elections, which the US called a "great achievement" while pledging "continued international support".
It is the country's first democratic transfer of power.
Preliminary results for the presidential poll are not due until April 24 and a run-off election is scheduled for May, if there is no outright winner.
There is no clear favourite but front-runners include Zalmai Rassoul, a former foreign minister; Abdullah Abdullah, the runner-up to Karzai in the 2009 election; and Ghani, a former World Bank academic.
Whoever succeeds Karzai must lead the fight against the Taliban without the help of US-led troops, who are due to pull out by the end of 2014, and also strengthen an economy that currently relies on aid money.
Not afraid of the Taliban
The Taliban had urged their fighters to target polling staff, voters and security forces, but there were no major attacks reported during the day.
Thousands lined up outside polling centres in Kabul, which has been hit by a series of deadly attacks during the election campaign.
"I'm not afraid of Taliban threats, we will die one day anyway. I want my vote to be a slap in the face of the Taliban," housewife Laila Neyazi, 48, told the AFP news agency.
One blast in Logar province, south of Kabul, killed one person and wounded two, according to Mohammad Agha district chief Abdul Hameed Hamid.
Omar Daudzai, the interior minister, said four civilians, nine police and seven soldiers had been killed in violence on election day. He added that many attacks had been foiled, without giving further details.
Attacks or fear of violence had forced more than 200 of a total 6,423 voting centres to remain closed.