An explosion occurred near a polling station in the southern Afghan city of Kandahar on Saturday just an hour after voters began queuing to cast their vote to elect a new president.
A senior provincial government official said three people were injured by the blast.
No militant group claimed responsibility for the blast.
Fourteen candidates are registered but the race will likely come down to incumbent President Ashraf Ghani and his former deputy Abdullah Abdullah.
The winner will play a crucial role in the country’s quest to end the war with the Taliban and the resumption of talks between the insurgents and the United States that were called off earlier this month.
The hard line insurgent group, which controls more of the country than at anytime since its regime was toppled in 2001, has threatened voters to stay away from the election or face dire consequences.
To protect voters and polling stations from Taliban attacks tens of thousands of Afghan forces were deployed across 34 provinces.
About 9.6 million of Afghanistan’s 34 million people are registered to vote for one of the 14 candidates at around 5 000 polling centers that will be protected by some 100 000 Afghan forces with air support from US forces.
“Bravado gets defined when one musters courage to cast their vote in Afghanistan,” said Roya Jahangir, a doctor based in the capital of Kabul.
Jahangir said she and her husband will cast their votes even if it means standing in long queues for hours.
“We hope this time there is no fraud otherwise voters will feel cheated once again.”
Media showed lines of men and women outside numerous polling stations, indicating strong turnout in some areas.
In the northern province of Balkh, voters waited for election officials to arrive at polling stations set up in schools, colleges, mosques, hospital campuses and district centres.
An explosion inside a polling station in the southern Afghancity of Kandahar was confirmed by local officials, as witnesses said an ambulance rushed to the area.
Explosions also hit the Afghan cities of Kabul, Ghazni and Jalalabad, officials said.
More than 400 polling centers will remain closed because they are situated in areas under Taliban control. Hundreds more will be closed because of security concerns.
The election is the fourth presidential vote since the fall of the Taliban to US-led forces
