Antigovernment protesters were beaten back by swarms of riot police officers on Sunday Evening when they tried to storm the Belarus government headquarters here in an outburst of anger and frustration over the apparent and, many said, wholly unsurprising re-election of the country’s authoritarian president, Aleksandr G. Lukashenko.
Thousands of people converged on Independence Square here in the capital, heeding opposition leaders who called Sunday’s election a farce and accused Mr. Lukashenko of keeping the post-Soviet country locked in dictatorship.
Official election results released by the government early Monday morning showed Mr. Lukashenko with 79.7 percent of the votes cast, Reuters reported.
Svetlana Vizgina, a 30-year-old foreign-language teacher, said she checked an option on the ballot marked “against all” candidates. “Conditions were inadequate for an election,” she said.
The protesters chanted slogans like “Long Live Belarus” and disparaged Mr. Lukashenko, who in 16 years as president has muzzled the news media, eliminated political opponents and emboldened the secret police.
At one point, protesters charged the entrance of the imposing government headquarters, breaking through glass doors and trying to push through barricades that had been erected inside.
But armored riot troops quickly overwhelmed the protesters, at times funneling them toward packs of plainclothes officers who beat them.
Earlier in the evening, one of the leading opposition candidates, Vladimir Neklyaev, appeared to have been beaten unconscious in a separate attack.
He was taken to a hospital, but one of his aides said seven men wrapped him in a blanket and carried him away, as his wife screamed from a locked room, the Associated Press reported.
The protests echoed similar demonstrations in 2006 after an earlier re-election of Mr. Lukashenko. Those protests were easily quashed.
By late Sunday evening, police officers wielding shields and clubs occupied large swaths of downtown Minsk, and protesters had begun to disperse.
It was unclear how many arrests had been made, though there were reports that several opposition leaders had been detained.
Earlier in the day, Mr. Lukashenko suggested that the authorities would take steps to ensure that the opposition would not be able to gather to protest the results. Speaking to reporters after casting his vote at a large athletic complex, he called members of the opposition “bandits and saboteurs.”
“For half a year, people have been saying these elections will be unfair,” he said. “Today my fate and theirs is being decided by the people of Belarus, and only the people of Belarus.”
Yet even before the polls closed Sunday, opponents of Mr. Lukashenko’s began complaining of a police crackdown.
Opposition activists said that several of their colleagues had been arrested by midafternoon, though it was unclear what the charges were.
Julia Rymashevsky, a spokeswoman for Mr. Neklyaev, said at least two 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.
Later, Mr. Neklyaev was headed to the central square to join the protest with about 100 or so followers when they were attacked without warning by men who wore black masks and clothing with no insignias. The men tossed stun grenades and began attacking people.
A reporter and a photographer for The New York Times were among those who were beaten, but they were not seriously injured. 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. After he was reportedly removed from the hospital, his whereabouts were unknown.
It did not appear that other opposition candidates were initially targets of the riot police on Sunday night. The large protest in central Minsk lasted for several hours before the police moved in.
“It was horrible,” said Tatyana Molosh, a student. “I was barely able to get out. From one side the police were moving in, and then they came in from the other side.
“But, you know what the most frightening thing is?” Ms. Molosh said. “I am 25 years old and I have to build a future and a family in this country and I see no future. This is the saddest thing.”
Such complaints are nothing new in Belarus, particularly among the young, many of whom see little opportunity for success or growth in a country with an economy largely dependent on handouts from other countries.
The rising tensions on election night belied a concerted attempt by Mr. Lukashenko to make these elections appear more democratic in an effort to get money from the West as relations with his longtime patron, the Kremlin, have declined.
Many Western countries, particularly in the European Union, have appeared heartened by these developments, and have sought to engage Mr. Lukashenko. Poland and Germany recently offered Belarus $3.5 billion in aid if this election was deemed free and fair.
In Minsk, however, few held out hope that it could be. “We have the ability to campaign and give people information,” said Alesya Yakubouskaya, a student and opposition supporter. “But this is just so the government can show that it is liberal and that these elections will be fair.”