On Sunday up to 10,000 people marched through the snow-bound capital Minsk chanting "Out!," "Long Live Belarus!" and other anti-Lukashenko slogans in one of the most significant challenges yet to his iron-fisted, 16-year rule.
Then riot police waded in, beating people with batons on Independence Square, a Reuters reporter at the scene said. Some protesters in the ex-Soviet republic threw stones and snowballs at police.
Several people were left sprawled on the ground, including an elderly woman who had been hit on the head. Others were bundled into police cars. The opposition reported at least three candidates detained.
One of them, 56-year-old Andrei Sannikov, had earlier told the crowd: "Down with the rule of Lukashenko, freedom for Belarus!"
Another, Vladimir Neklyayev, was beaten by police who fired shots into the air to disperse a column of his supporters trying to join the main rally, a Reuters witness said. His wife said he was later taken by police from his hospital bed, where he was recovering from head injuries.
The Interior Ministry accused Neklyayev's supporters of provoking the clash.
Early on Monday the state electoral commission said Lukashenko had won 79.7% with 100% of votes counted. It put voter turnout in sub-zero temperatures at more than 90%.
The opposition says Lukashenko rigged the vote.
EU watching closely
The European Union is watching closely, weighing how far to engage with the country of 10 million on its eastern flank, amid tension between Lukashenko and chief benefactor Russia.
The head of the European Parliament, Jerzy Buzek, said the incident involving Neklyayev was unacceptable. "This cowardly attack on a defenceless candidate for President of Belarus is outrageous and disgraceful," he said in a statement.
An aide to nationalist candidate Grigory Kostusev said the 53-year-old had been stopped in his car and arrested.
In the main rally, some demonstrators broke the glass doors to the government building but were restrained by others in the crowd, a Reuters reporter said.
Veteran leader Lukashenko, 56, had earlier scoffed at the opposition's plans to protest against the conduct of the election. He predicted nobody would turn out.
During Lukashenko rule Belarus's command economy has been propped up by energy subsidies from chief ally Russia. The country serves as a buffer between Russia and NATO and a transit route for Russian gas heading to Europe.
But relations with Moscow have been on the rocks in recent years, and the moustachioed former state farm director has been courting the West.
The European Union has dangled the prospect of financial aid if Sunday's vote is deemed fair. It will take its cue from monitors from the Organisation for Security and Cooperation in Europe (OSCE), who report back on Monday.
The OSCE had said on Sunday that the election already appeared "better" than in 2006.
One opposition figure told protesters on October Square that, according to an unofficial opposition exit poll, Lukashenko won only 30.7% against Neklyayev's 18%. He called for a second round of voting.
State security forces gave a warning on the eve of the vote that they would crack down on attempts to "whip up tension."
Lukashenko crushed dissent harshly in the early years of his rule, jailing opponents and muzzling the media. He was dubbed Europe's 'last dictator' by the Bush administration.
(EurActiv with Reuters.)