Explosion took place outside a polling centre in the city of Kandahar.

Afghans voted in presidential elections amid tight security Saturday, even as insurgents attacked polling centres in a series of blasts across the country that left at least one person dead.

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

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 targeting residents as they cast their votes.

By midday, the toll appeared relatively light compared to previous elections, though Afghan national authorities provided little, if any, information about reported blasts.

One person was killed and two others wounded in an explosion near a polling centre in Jalalabad in the eastern province of Nangarhar, provincial governor's spokesman Attaullah Khogyani said.

And at least 16 people were wounded in the southern city of Kandahar when a bomb went off at a polling station, a hospital director told AFP, while officials across the country reported several small explosions at other election sites.

The Taliban, who unleashed a string of bombings during the two-month election campaign, claimed to have hit several polling stations.

Having voted at a high school near the presidential palace in Kabul, Ghani said the most important issue was finding a leader who could bring peace to the war-torn nation.

"Our roadmap (for peace) is ready, I want the people to give us permission and legitimacy so that we pursue peace," Ghani said.

Some 9.6 million Afghans are registered to vote, but many have little faith that after 18 years of war any leader can unify the fractious country and improve basic living conditions, boost the stagnating economy or bolster security.

Still, voters braved insurgent attacks and long queues to cast a ballot.

"I know there are security threats but bombs and attacks have become part of our everyday lives," 55-year-old Mohiuddin, who only gave one name, told AFP.

"I am not afraid, we have to vote if we want to bring changes."

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 and forced then-US president Barack Obama to push for a compromise that saw Abdullah awarded the subordinate role.

"The only request I have from the election commission is that they ensure the transparency of the election because lots of people have lost their trust," Afghan voter Sunawbar Mirzae, 23, said.

Problems voting

Voting in Afghanistan's fourth presidential election was supposed to take place at some 5,000 polling centres across the country but hundreds have been closed to the abysmal security situation.

Many Afghans said voting had gone smoothly, triumphantly holding up fingers stained in indelible ink to show they had cast a ballot, but several said they had experienced problems.

"I came this early morning to cast my ballot. Unfortunately my name was not on the list," said Ziyarat Khan, a farmer in Nangarhar. "The whole process is messy like the last time."

Campaigning was hampered by violence from the first day, when Ghani's running mate was targeted in a bomb-and-gun attack that left at least 20 dead.

Bloody attacks have continued to rock Afghanistan, including a Taliban bombing at a Ghani rally last week that killed at least 26 people in the central province of Parwan near Kabul.

The interior ministry says 72,000 forces will help to secure polling stations.

Election officials say this will be the cleanest election yet, with equipment such as biometric fingerprint readers and better training for poll workers to ensure the vote is fair.

Still, the US embassy in Kabul has said it is "disturbed by so many complaints about security, lack of an equal playing field and fraud" and many Afghans say they have no intention of voting, citing fraud and security fears.

Saturday's poll was initially slated to take place in April, but was twice delayed because election workers were ill-prepared, and the US was leading a push to forge a withdrawal agreement with the Taliban.

That deal has been scuppered for now after US President Donald Trump pulled out and Afghanistan's next president will likely face the daunting task of trying to strike a bargain with the Taliban.

Results are not expected until October 19. Candidates need more than 50 percent of the vote to be declared the outright winner, or else the top two will head for a second round in November.