An explosion occurred near a polling station in the southern Afghan city of Kandahar on Saturday just an hour after residents began voting to elect a new president.
A hospital official said 15 people were injured in the blast.
Polls opened amid high security due to threats from an insurgent Taliban.
The war-torn country’s Ministry of Interior Affairs said 72,000 troops would be in force to protect 5,000 polling centers set up across Afghanistan.
The Taliban has warned that those involved in the electoral process would be attackedusing any means at its disposal.
Deputy Interior Minister General Khushal Sadat called on Afghans to exercise their democratic right, while also allaying fears over their security.
More than 9.6 million people have registered for the election, according to the Afghan Independent Election Commission (IEC), of which about a third are women. Nevertheless, a low turnout is expected due to experts warning of widespread fraud and safety fears.
Eighteen candidates registered with the IEC as presidential hopefuls with the two favorites being current president Ashraf Ghani, and his Chief Executive Abdullah Abdullah.
The build-up to the election has been turbulent, with hurried campaigns partly due to the US-Taliban negotiations falling through.
All candidates in the race — Ghani and Abdullah in particular — have held campaign rallies in different Afghan provinces. But observers believe the campaigning has not been enough to reach voters.