Belarus' main opposition leader has urged his supporters to keep up daily protests against the election result, calling for a major rally on Saturday.
Alexander Milinkevich was addressing a few thousand protesters who had gathered in a Minsk square to complain of vote-rigging in Sunday's poll.
Ambassadors from 11 EU countries went to the square earlier to show support.
British ambassador Brian Bennett said Europe was dissatified over what had been a "fraudulent vote".
The protesters accuse President Alexander Lukashenko of rigging the presidential poll and want a new vote.
The EU and US have condemned the poll as flawed and the EU has said it may impose sanctions. But Russia says the poll was fair.
Results announced on Monday gave Mr Lukashenko 82.6% of the vote, securing his third term in office.
Electoral officials said the runner-up Mr Milinkevich polled 6%.
Mr Milinkevich said he was going to spend another night with his supporters camped out in the square.
He called for a big show of strength in the Belarussian capital on Saturday - the anniversary of the declaration of independence of the short-lived Belarussian republic in 1918.
"We will come here every day until 25 March to speak about freedom. Bring your friends and acquaintances. We will gather many people," the head of the United Civil Party said.
He spoke by the light of TV cameras after the lighting in October Square was shut off.
The opposition said on Tuesday that four activists had been arrested during the protest.
In a small-scale echo of Ukraine's "Orange Revolution", protesters have put up 17 tents in the square. They have put candles and food on plastic sheets and have been playing music from loudspeakers.
Opposition turns to internet
They said they would continue their protest in sub-zero temperatures until a new election was called - but such an outcome is unlikely, the BBC's Steve Rosenberg reports from Minsk.
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.
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.
Mr Lukashenko has said he believes voters have made their choice and that any attempts to launch a revolution have failed.
In a television appearance on Monday, the president insisted the poll was fair and democratic and called the complaints "absurd".
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 US, which has previously labelled Mr Lukashenko a dictator, says it does not accept the result.
But a rival observer mission, from the Russian-led Commonwealth of Independent States, said the election was open and transparent.