Insurgents worked to disrupt Afghanistan's presidential election Saturday, with a series of blasts reported across the country as voters headed to the polls and troops flooded the streets of the capital.

The vote marks the culmination of a bloody election campaign that is seen as a two-horse race between President Ashraf Ghani and his bitter rival Abdullah Abdullah, the country's chief executive.

The Taliban, who unleashed a string of bombings during the two-month campaign, in recent days issued repeated warnings they intend to attack polling centers.

At least 15 people were wounded in the southern city of Kandahar when a bomb went off at a polling station about two hours after voting began, a hospital director told AFP, and officials across the country reported several small explosions at other election sites.

'Peace is the first desire of our people,' Ghani said after casting his vote at a high school in Kabul.

'Our roadmap (for peace) is ready, I want the people to give us permission and legitimacy so that we pursue peace.' Wary authorities placed an uneasy Kabul under partial lockdown, flooding streets with troops and banning trucks from entering the city in an effort to stop would-be suicide bombers attacking the electoral process.

The capital's traffic, often gridlocked, dropped to a trickle as schools and offices closed for the day and as many people chose to stay off the roads.

Some 9.6 million Afghans are registered to vote.

Abdullah and Ghani both claimed victory in the 2014 election a vote so tainted by fraud and violence that it led to a constitutional crisis.

At time, then-US president Barack Obama pushed for a compromise that saw Abdullah awarded the subordinate role