Afghans headed to the polls on Saturday morning to choose a successor to President Hamid Karzai and seal the first ever democratic transfer of power in the country's history.



The run-off election is the second voting day in less than three months after no candidate won more than 50% in the April poll.



The last vote was hailed as a huge success after voters turned out in unexpectedly high numbers and a barrage of Taliban attacks did little to disrupt polling. Still, the drawn-out election process has been a huge challenge for a desperately poor country in the grip of a tenacious insurgency.



There were fears on Saturday that voters might stay away after the emotion of the first round dissipated and the Taliban ramped up their threats. But the weather co-operated and on a sunny morning queues formed outside polling stations around the country before their 7am opening.



“It's the duty of all Afghans to go and vote,” said 35-year-old Kabul shopkeeper Ahmad Qaseem, waiting outside a city centre polling station for the doors to open. “If we vote it helps our country, if we don't it benefits the Taliban. The biggest challenge will be to provide security in the provinces – in Kabul it is OK.”



The election pits former foreign minister and mujahedeen Dr Abdullah Abdullah, who won 45% of the vote in the first round, against World Bank technocrat and former finance minster Ashraf Ghani, who claimed 32%.



The incumbent Karzai was barred by the constitution from standing again after more than a decade in power. He will hand the winner a poor country whose government is riddled with corruption, almost entirely dependent on foreign aid and facing off against a hardened insurgency.



Hamid Karzai casts his vote at a polling station in Kabul in the presidential run-off. Photograph: Jawad Jalali/EPA Photograph: Jawad Jalali/EPA

The Taliban replaced their military commander and have threatened bloodshed after the first round of voting was hailed worldwide as a victory for the government.

They fired several rockets at Kabul airport in the early morning of Saturday but did not cause any casualties. There were some reports of fighting in other parts of the country but no major attacks in the big urban centres where many people either live or were bussed in to cast their votes.



The other major concern is fraud after hundreds of thousands of votes were thrown out in the first round. Both candidates have deployed thousands of observers to monitor polling stations across the country and accusations of cheating began even before voting.



On Friday evening supporters of the two camps both sent out the same photo on Twitter purporting to show soldiers with pre-marked ballot papers. The only difference was which candidate had been selected – each camp showed the tick next to their rival's name.

