Afghans have begun voting for a new president in what will be the nation's first ever transfer of power through the ballot box.

A massive security operation is under way to thwart the Taliban which has vowed to disrupt the election.

Eight candidates are vying to succeed Hamid Karzai, who is barred by the constitution from seeking a third consecutive term as president.

The poll has already been overshadowed by the shooting of two journalists.

Award-winning German photographer Anja Niedringhaus was killed and veteran Canadian reporter Kathy Gannon was injured when a police commander opened fire on their car in the eastern town of Khost on Friday. They had both worked for Associated Press for many years.

It was the latest in a string of deadly attacks that have marred the lead-up to the election.

(BBC)