The two constables died in separate shootings in the same eastern province where police also found a landmine near a polling station, a police official said.

"It's possible the attacks and the landmine were aimed at disrupting the election" Thursday, the official told AFP, speaking on condition of anonymity. "But we've strengthened security with more policemen."

Surveys suggest the vote is a tight race between the present and former prime ministers of the island, racked by a decades-old ethnic conflict between the Sinhalese majority and Tamil minority.

Heavily armed troops were backing 64,000 police deployed to guard more than 10,000 polling booths and 22 counting centres across the island, police said.

"We have also deployed a special motorcycle unit that will respond to emergencies in key areas," police chief Chandra Fernando said.

Thousands of public servants deployed to conduct the election were on the move Wednesday, travelling to far-flung areas to set up polling booths for the 13.3 million voters.

"Everything is in place now," Elections Commissioner's spokesman Rasika Peiris said.

Peiris said international and local election monitors from two private organisations will be allowed access to polling stations. The European Union is deploying 72 foreign observers.

In the town of Galle, 112 kilometres (72 miles) south of Colombo, local election chief Dias Punchihewa was overseeing final preparations to stage the vote in the tsunami-hit coastal district.

"At each and every polling station there will be two police constables and at vulnerable ones it will be three or four," Punchihewa said.

Several roads in the capital were closed Wednesday as part of tight security for the main election secretariat and the counting centre.

Mobile patrols were stepped up together with an increase in checkpoints manned by troops and police, Colombo's deputy Police Inspector-General Pujith Jayasundara said.

Thursday's election is the fifth national vote to be held in the island of 19.6 million people in five years.

Although there are 13 men running, only Prime Minister Mahinda Rajapakse and opposition leader Ranil Wickremesinghe are seen as serious contenders.

Former premier Wickremesinghe has been given a slight lead in a private opinion poll, but most analysts say the election is too close to call.

However, with local media reports that minority Tamils who are potential kingmakers may vote for the market-friendly Wickremesinghe, the tiny Colombo Stock Exchange saw a major rally.

Prices leapt four percent in the first three hours of trading on expectations that the Tamil vote will tip the scales in favour of Wickremesinghe, brokers said.

With the majority Sinhalese community split down the middle between the two main candidates, the Tamils who usually vote as one bloc could decide who rules the country.

"The Tamil vote could be the deciding factor," said Sunanda Deshapriya, a director at the Centre for Policy Alternatives. "The question is if they will be able to vote freely."

There will be no polling in Tamil Tiger rebel-held territory in the northeast, but the authorities are arranging transport to allow civilians to cross frontlines and vote in government-held areas.

Troops and Tigers have been observing a truce since February 2002.

The rebels have said they are not interested in the election and have stopped short of calling for a boycott.

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