The opposition in Belarus says four leading activists have been arrested by police in Minsk during a protest against the election result.
Icy conditions did not deter hundreds of opposition activists
Opposition supporters defied police and braved sub-zero temperatures overnight, camping out in a central square. The crowd now numbers about 150.
The protesters accused President Alexander Lukashenko of rigging the vote and demanded a fresh election.
The EU and US have condemned the poll as flawed, but Russia says it was fair.
Results announced on Monday gave Mr Lukashenko 82.6% of the vote, against 6% for the runner-up Alexander Milinkevich.
Mr Milinkevich's campaign manager Anatoly Lebedko and three other top aides in his United Civil Party campaign team have been arrested, Mr Milinkevich's spokesman said.
The other three were named as Alexander Dobrovolsky, Alexei Yanukiyevich and Valentina Pavelikova.
They were arrested as they returned to the rally after going to fetch food.
Protests began on Sunday evening as the polls closed, with some 10,000 people gathering in October Square.
Thousands turned out again on Monday night, but numbers later dwindled to several hundred.
"Our protest will be strong and long," Mr Milinkevich told the crowd. "We will never recognise this election.
"It's not an election but an anti-constitutional seizure of power."
One young man in the square told the BBC "this is the last chance to change the situation".
"Many people helped us, they brought hot water, hot tea and some meals... it's a bid for freedom and the people standing here don't want to be slaves," he said.
In a small-scale echo of Ukraine's "Orange Revolution" the protesters erected 17 tents, put candles and food on plastic sheets and played music from loudspeakers.
They said they would continue their protest until a new election was called - but such an outcome is unlikely, the BBC's Steve Rosenberg reports from Minsk.
The EU says it is likely to impose sanctions.
Mr Lukashenko has said he believes voters have made their choice and that any attempts to launch a revolution there have failed, our correspondent says.
In a television appearance on Monday, the president insisted the poll was fair and democratic and called the complaints about it "absurd".
"Despite the unashamed foreign attempts to dictate to us and colossal external pressure, they have failed to break us," he said.
Official figures say the election turnout was 92.6%. The result gives the president, in power since 1994, a third term in office.
However, the OSCE, Europe's main election monitoring body, said the process had been "severely flawed", with harassment of opposition activists, biased media coverage and obstruction of independent monitors.
The White House, which has previously labelled Mr Lukashenko a dictator, says it does not accept the result.
White House spokesman Scott McClellan said: "We applaud democrats in Belarus for their courage and peaceful stand to reclaim their freedom. We support their call for a new election."
But a rival observer mission, from the Russian-led Commonwealth of Independent States, said the election was open and transparent.
Russian President Vladimir Putin sent Mr Lukashenko a congratulatory message saying: "The results of the election demonstrate the confidence of the electorate in your policies."