Sri Lanka's [Images] presidential elections opened on Thursday morning amid tight security after at least six people were killed in the eastern province on the eve of the polls.

People began trickling into voting booths at 7.00 am local time, even as party officials feared violence will discourage people in the multi-ethnic east from voting.

About 13.3 million people are eligible to vote in the presidential election, Sri Lanka's fourth in six years.

Though 13 candidates are running for the top job, the fight is believed to be between incumbent Prime Minister Mahindra Rajapakse and the Leader of Opposition Ranil Wickremesinghe.

Both are members of the majority Singhalese community that appeared split over the two, leaving the minority Tamils in the role of the kingmaker.

The winner will replace outgoing President Chandrika Kumaratunga, who lost a court bid to remain in office.

The future of the peace process as well as Sri Lanka's worsening economy due to decades of war and tsunami rehabilitation are the key issues in the election.

Security was tight with more than 60,000 policemen and 8,000 soldiers guarding booths at the over 10,000 polling stations following Wednesday's killings of three Singhalese, two Tamils and one Muslim which analysts say could have been a bid to scare away members of those communities from polling booths.

The final result is expected by noon on Friday.

Residents in the embattled northeast areas, parts of which are controlled by the Liberation Tigers of Tamil Eelam, said voting was initially slow with few Tamils leaving rebel-held territory to vote.

The LTTE has not indicated that they support either of the two main contenders but has allowed the Election Commissioner to send buses into their areas to provide transport for Tamil voters to make their way to poll booths located in government-controlled places.

Analysts say that the fortunes of the two front-runners depends on how the LTTE will influence Tamil voters and whether they will cast their ballot at all.

Speculation in local newspapers expected the Tamils to cast a vote for Wickremesinghe who favours Norway-backed peace talks with the rebel LTTE.

The rebels are observing an Oslo-brokered truce with the military, which has stopped open warring but is still breached almost daily by killings and other violent incidents.

Another significant group, the Tamils of recent Indian Origin are also expected to choose Wickremesinghe in line with a pre-poll pact between the two parties.