Thousands of polling centers across Afghanistan opened for voting on Thursday, and millions of Afghans were expected to choose a new president to lead a nation plagued by armed insurgency, drugs, corruption and a feeble government.
Turnout, particularly in the violent south, will be key to the vote's success -- the country's second direct presidential election. Taliban militants have pledged to disrupt the vote and have circulated threats that those who cast ballots will be punished.
"Yes, we are going to vote," Abdul Rahman, 35, said as he stood 50 meters outside a polling center in Kabul. He and his friends were waiting to see a line of people go inside and vote safely before casting ballots. "If anything happens to the polling centre, we don't want to be too close to it."
Helicopters circled overhead in the capital as police manned extra checkpoints. In one northern Kabul neighborhood, a car with loudspeakers encouraged people to vote.
Karzai, who has held power since the Taliban was ousted eight years ago, is favored to finish first among 36 official candidates, although a late surge by former Foreign Minister Abdullah Abdullah could force a runoff if no one wins more than 50 per cent.
Preliminary results were expected to be announced on Saturday Kabul time.
Violence has risen sharply in Afghanistan the last three years, and the US now has more than 60,000 forces in the country close to eight years after the US invasion following the September 11 attacks of 2001.