here are eight contenders battling it out in Afghanistan's presidential elections.

But political observers have pinpointed three they say are the most likely to win.

Former foreign minister Zalmai Rassoul has been one of the closest confidantes of incumbent President Hamid Karzai.

He's also held security roles.

Critics say he'd lack the strength and independence to make a break from the old administration accused of perpetuating a culture of corruption and inefficiency.

Abdullah Abdullah's been in the race before.

He came second after Karzai in the 2009 elections but withdrew from the run-off citing concerns about mass vote fraud.

He's also a former foreign minister but is best known for championing the rights of Afghan Tajiks, the country's second largest ethnic group.

And then there's Ashraf Ghani Ahmadzai.

The US-trained anthropologist returned to Afghanistan after the Taliban was toppled.

He's held several government posts including that of finance minister.

He also ran in the 2009 elections in which he came fourth.

He's among the strongest backers of the bilateral security deal to keep U.S. troops in Afghanistan beyond 2014 that Karzai has refused to sign.

To win outright a candidate needs to get more than half the vote.

Given the country's diverse ethnic and racial differences most analysts predict a run-off between the top two contenders.