By Olena Horodetska
MINSK (Reuters) - Belarussian president Alexander Lukashenko looked set for election victory on Sunday, but liberal opponents defied his warnings and thronged central Minsk, denouncing the poll as rigged.
Lukashenko, accused by the West of crushing human rights and falsifying elections during 12 years in power, says his rivals are Western-funded troublemakers. In the campaign's final days, he vowed to "wring the necks" of anyone violating public order.
In one of the largest opposition rallies in Belarus in recent years, at least 10,0000 demonstrators defied official warnings to stay away and converged on central October Square after polls closed.
Police at the scene were not impeding the demonstrators, who were waving dozens of European Union and blue opposition flags and the white and red national colours banned by Lukashenko. But witnesses said riot police were massing in adjacent streets.
Braving freezing temperatures and snow, many brought flowers in a sign that their protest was peaceful.
"I came here because it is our last chance to change something in this country," said Yevgeniy, 19, student.
Following mass upheavals that brought pro-Western leaders to power in Georgia and Ukraine, Lukashenko has taken no chances, securing passage of tough legislation against illegal assembly.
Election officials said turnout of the just over seven million voters stood at about 90 percent by 4 p.m. British time. Preliminary results are expected by midnight.
Long before voting ended, two pro-government institutes had issued "exit polls" showing Lukashenko capturing more than 80 percent to about four percent for his main rival.
Main opposition hopeful Alexander Milinkevich denounced the election as fraudulent.
"The results will be unrealistic and falsified," Milinkevich told reporters. "We will not recognise them and nor will democratic countries. This is already clear."
Lukashenko, known as "batka" or father, tells Belarussians he has offered stability and remains popular among elderly and rural voters.
The president was decidedly more measured on voting day than in the run-up to the poll.
"We will react appropriately to things depending on the circumstances," a beaming Lukashenko said at his polling station. "The campaign is proceeding in a calm, ordinary fashion as in previous years."
But he hit back at longstanding U.S. allegations that Belarus was the "last dictatorship in Europe", denouncing President George W. Bush as "terrorist no. 1 on the planet".
Both the European Union and the United States vow to boost sanctions against Belarus if hundreds of independent observers now in Belarus -- many from the Organisation for Security and Cooperation in Europe -- say the vote is unfair.
Despite Kremlin leader Vladimir Putin's distaste for the president, Russia will almost certainly give quiet approval to the poll as Belarus is its only ally on its western borders.
A second opposition hopeful, Alexander Kozulin, urged supporters to keep their cool at mass gatherings.
"Do not give the authorities cause to shed blood today and use force against peaceful citizens," he said in a statement.
The fourth candidate is an ally of the president.
Lukashenko dismissed any criticism of the poll's conduct.
"The Belarussian people are masters in their own country," he said.
Law enforcement bodies, backed by state television, accused the president's opponents in the final days of campaigning of using the poll as a screen to seize power. Residents have been warned to stay off the streets for fear of violence.