Heavily armed riot police tossed stun grenades and battered opposition activists with truncheons on Sunday night here as they broke up a gathering to protest the conduct of Belarus’s presidential election.
The violence erupted without warning as a group of 100 or so supporters of an opposition candidate was walking peacefully toward a central square in Minsk, the capital, where several candidates were planning to hold a united demonstration against the Belarus president, Aleksandr G. Lukashenko.
Mr. Lukashenko, often referred to as Europe’s last dictator, had earlier in the day suggested that the authorities would take steps to ensure that the opposition would not be able to gather to protest the results. He is expected to easily win another term, after balloting that his rivals maintain was not free and fair.
On Sunday night, Vladimir Neklyaev, an opposition candidate, was leading his supporters on a march to the central square when scores of riot police arrived, tossed stun grenades and began attacking people.
A reporter and a photographer for The New York Time were among those beaten up. The police slammed people to the ground and held them there for several minutes, pushing their heads into the snow, before suddenly leaving.
Mr. Neklyaev appeared to have been knocked unconscious in the assault and was carried back to his campaign headquarters by his supporters.
It did not appear that other opposition candidates were targets of the riot police on Sunday night, and several thousand people were able to gather on the square for the demonstration.
Earlier in the day, even before the polls had closed in the presidential election, Mr. Lukashenko’s rivals said the police were conducting a crackdown to prevent an anti-government demonstrations.
Opposition activists complained that several of their colleagues had been arrested by mid-afternoon, though under what pretext was unclear. Julia Rymashevsky, a spokeswoman for Mr. Neklyaev, one of nine opposition candidates, said at least two campaign aides had been arrested, including one who seemed to just disappear.
“He called a taxi and left his apartment, but he never made it to the taxi,” Ms. Rymashevsky said.
Opposition leaders have vowed to protest what they say will inevitably be a fraudulent election. Few here have much doubt that victory will go to Mr. Lukashenko, who has never lost in 16 years as ruler of this former Soviet-republic. Independent monitors have never considered elections here much more than farce.
The authorities had warned opposition leaders to call off their protest and vowed to prevent any of them from gathering after polls closed Sunday evening.
“Don’t worry,” Mr. Lukashenko said, after casting his vote at a large athletic complex on Sunday. “There will be no one on the square tonight.”
The rising tensions on election night belied a concerted attempt by Mr. Lukashenko to make these elections appear more democratic in an effort to court the West amid increasingly sour and unpredictable relations with his longtime patron, the Kremlin.
After a meeting with Mr. Lukashenko last month, the foreign ministers of Poland and Germany said that the European Union could be willing to give Belarus $3.5 billion in aid, but only if the elections were deemed free and fair.
And so, with his country reeling under the stresses of the financial crisis, Mr. Lukashenko seemed to be softening his stance toward his opponents.
Ahead of these elections, opposition candidates received free airtime on national television and had been largely allowed to campaign across the country, though not without the occasional harassment by the local police.
For the first time, candidates were permitted to hold televised debates. Mr. Lukashenko did not participate, though other candidates were able to criticize the president free of censorship live on government-controlled television.
Mr. Lukashenko’s government maintains complete control over the vote count, with opposition figures making up less than 1 percent of local commissions tasked with providing the final tally. The president also received nearly 90 percent of all news coverage during the campaign, according to election monitors, who also expressed concern that ballots cast during a five-day early voting period could be tampered with.
“There have been certain improvements in a number of areas,” said Jens-Hagen Eschenbaecher, a spokesman for the election-monitoring wing of the Organization for Security and Cooperation in Europe. “But this was not enough to create an even playing field for all candidates during this campaign.”
For those campaigning for the opposition out in the snow-bound streets of Minsk recently, there was little question of who had the advantage.
Sergei Pradzed, a 23-year-old who was passing out fliers by the train station here, said he spent 14 hours in a frigid prison cell in October and was fined $400, as much as he earns in a month, for holding a sign that said, “Where are my rights?” on the capital’s central square. His protest did not fall within the government’s definition of campaigning.
“It does not matter to them how much we campaign,” Mr. Pradzed said. “They can get the results they want without effort.”
Despite Mr. Lukashenko’s dubious commitments to his new democratic experiment, the European Union and, to a lesser extent, the United States, have cautiously begun to engage him. Once a pariah in the West, he has recently been invited to European capitals and offered investment opportunities in exchange for at least a modicum of political openness at home.
In October, the European Union extended a repeal of travel restrictions for Mr. Lukashenko, “in order to encourage progress,” according to a statement by the Council of the European Union. It left in place sanctions aimed at the financial holdings of Belarussian officials.
At the same time, Western governments and nongovernmental organizations have drastically rolled back financing for opposition movements and candidates committed to toppling Mr. Lukashenko, succumbing to what one member of a Western nongovernmental organization said was a “fatigue with the fight.”
Rather, it is Russia, a country with its own democratic shortcomings, that has become one of Mr. Lukashenko’s biggest critics. This summer, Russia’s government-controlled news media started a propaganda assault portraying him as a Hitler-loving tyrant in a series of documentary films.
The criticism became so intense that it appeared to many observers, not least Mr. Lukashenko, that the Kremlin was preparing the ground for his ouster. At one point, Mr. Lukashenko directly accused the Kremlin of financing opposition forces in Belarus. In response, Russia’s president, Dmitri A. Medvedev, said Mr. Lukashenko seemed to lack basic human decency.
Russia’s leaders also praised elections that independent observers condemned as farce, and ignored persistent claims of trammeled human rights and civil liberties in this country of 10 million.
But the Kremlin seems to have grown weary of Mr. Lukashenko, who briefly cut off Russian natural gas flows through Belarus to Western Europe this summer amid a pricing dispute with Moscow, and refused to follow Russia in recognizing the independence of two separatist Georgian enclaves, among other offenses.
Russia has eased up a bit lately, deciding this month against imposing oil duties and raising natural gas prices for Belarus, in a move observers said might indicate Moscow’s willingness to at least recognize Mr. Lukashenko’s victory.
Still, Russian television has continued its attack, while giving fawning coverage to opposition candidates and reporting ominous warnings about potential fraud.
“Belarussian elections are like ancient theater,” the correspondent for Russia’s government-owned First Channel, said in a recent report. “The only difference between the ancient Greeks and the modern Belarussians is that the former gathered for the joy of the process, while the Belarussians just hope for some kind of finale.”