(CNN) -- Belarusian President Alexander Lukashenko, who preliminary results show has easily won election to a fourth term, praised police actions in dispersing post-election demonstrators and castigated the protesters as "vandals and thugs."
"What (protesters) tried to carry out in Minsk yesterday is not democracy, it is banditism," Lukashenko said in a news conference Monday, according to Belarusian Telegraph Agency, or BelTA, the country's state-run news agency. "Vandals and thugs lost their human faces. They went utterly wild."
After the announcement that Lukashenko had prevailed with 79% of the vote Sunday, according to preliminary election results, opposition candidates and their supporters took to the streets in Minsk, the capital, and clashed with police.
Lukashenko said Monday that 639 people were arrested Sunday and remain in custody, according to BelTA.Those detained include presidential candidate Vladimir Neklyaev, he said. The Russian news agency Interfax earlier reported that Neklyayev was hurt in clashes with riot police.
Lukashenko told reporters that Neklyayev and Vitaly Rymashevsky, another candidate, were removed from a hospital and interrogated by authorities, Interfax said. He said he was told by Health Minister Vasily Zharko that Neklyayev's injuries were not serious, and that Rymashevsky "rushed to take shelter in a hospital" after being struck in the head.
Another candidate, Nikolai Statkevich, told state-run Russian news agency RIA Novosti that he, too, was beaten.
The country's Central Election Commission told BelTA that the voter turnout was 90% and that it had not received any complaints. However, the Organization for Security and Cooperation in Europe said that while the election showed improvement, "Belarus still has a considerable way to go in meeting its OSCE commitments."
However, Belarus' Interior Ministry, in a statement on its website, said the "overwhelming majority" of those arrested were "drunk unemployed people and students of various schools and universities, some of them under age."
"Actions like those wouldn't have been tolerated in any civilized country," Lukashenko told reporters Monday. "Nobody in the West would have been soft toward those thugs. Water cannons, tear gas, mass arrests of hooligans -- and they'd be done away with in no time."
The president said most of those arrested were under the age of 21. He said the court will decide their fate.
"They will be imprisoned only if the courts decide that, according to the law," Lukashenko said, according to BelTA. "I am not the one who puts people into prison. I have only one right -- to pardon people."
Lukashenko called the elections free and transparent, and he added police restored acted strictly according to the law, restoring order in seven and a half minutes.
Referring to the demonstrations, he said, "I did warn you that if any mess started, we'd have enough resources (to handle it)," BelTA and Interfax reported. "You guys took on the wrong person. I won't hide in a cellar. So let's put paid to it. There will no longer be any brainless democracy. We won't have the country torn to pieces."
One demonstration was in support of Neklyaev, who received 1.77% of the votes, according to the election commission. The election commission numbers, cited by BelTA, put the number of votes Statkevich received at 1.04%.
The OSCE has repeatedly expressed concerns over the status of civil and political rights in Belarus. It noted in its statement Monday the detention of candidates as well as activists, journalists and others.
"While voting on election day was overall assessed positively, the process deteriorated significantly during the vote count, with observers assessing almost half of vote counts monitored as bad or very bad," the organization said. "This undermined the steps that had been taken to improve the election."
"This election failed to give Belarus the new start it needed," said Tony Lloyd, who leads a short-term OSCE mission and heads the delegation of the organization's Parliamentary Assembly. "The counting process lacked transparency. The people of Belarus deserved better. And, in particular, I now expect the government to account for the arrests of presidential candidates, journalists and human rights activists."
Former U.S. Secretary of State Condoleezza Rice once called Lukashenko "the last dictator in Europe."
The president told reporters Monday that under his leadership, Belarus will drastically improve its economy in the next five years, and its standard of living will closely approach that of Europe.
Authorities used stun grenades on the demonstrators as they headed toward October Square in downtown Minsk, Interfax reported. However, several thousand people gathered in the square, chanting "For Belarus!" Some of them waved flags with the symbol of the Christians Democratic Party, led by Rymashevsky.
The Interior Ministry said authorities knew in advance that some presidential candidates planned to "stage unsanctioned mass rallies." The gatherings at first seemed peaceful, according to the ministry statement, but "turned into an attempt to seize the government building where the Central Elections Committee was located."
The building was attacked with sections of water pipes, stones and pieces of ice, breaking several windows, the ministry said, and protesters stormed inside. Police are working on identifying the organizers and participants, "as well as documenting their crimes and estimating the inflicted damage," the ministry said.
Russian President Dmitry Medvedev, speaking at a news conference broadcast on Russian state television Monday, said that Moscow expects Belarus to continue "to develop as a modern state based on democracy" after the election.
"No matter who the leader is, Belarus will always be one of the states closest to us," Medvedev said.
Lukashenko, who has been in office since 1994, was running against nine other candidates, the election commission said.
None garnered more than 2.5% of the votes, BelTA said.
Andrei Sannikov, a former diplomat who wants to see Belarus as a member of the European Union, was one of the main opposition leaders. The two others are Yaroslav Romanchuk and Neklyaev.
Economist Romanchuk, a candidate from the United Civil Party, has been prolific in publicizing his views on economic reforms. Meanwhile, Neklyaev ran a social campaign, "Tell the Truth!" He was arrested for participating in public protests earlier this year and later released.
CNN's Maxim Tkachenko and Mila Sanina contributed to this report.