Preliminary official results earlier give Lukashenko a victory in Sunday's election with 80 percent of the vote. Data shows Tikhanouskaya, a former English teacher who emerged from obscurity to become his main rival, won 9.9 percent of the vote.
Belarusian opposition presidential candidate Svetlana Tikhanouskaya has refused to recognise official results that hand incumbent Alexander Lukashenko a landslide re-election victory.
Preliminary official results earlier on Monday showed that Lukashenko had won 80 percent of the vote in Sunday's election, which gives him a sixth term in office.
Tikhanouskaya, a former English teacher who emerged from obscurity to become his main rival, won 9.9 percent of the vote, the data showed.
Tikhanouskaya told reporters in Minsk she considered herself the election winner, not Lukashenko.
She said the election had been massively rigged.
Her aides said the opposition wanted a vote recount at polling stations where there were problems.
They also said the opposition wanted to hold talks with authorities about how to bring about a peaceful change of power.
Central electoral commission chief Lidia Yermoshina has said in televised comments that the strongman's main challenger Svetlana Tikhanovskaya won 9.9 percent, citing a preliminary count.
The other three candidates each won less than two percent, Yermoshina said.
Protester killed, dozens arrested
Police in Belarus detained some 3,000 people for taking part in what it called unauthorised gatherings after post-election demonstrations on Sunday, the interior ministry said on Monday, accusing some protesters of sparking clashes with police.
The ministry said in a statement that 1,000 of the detentions were in the capital Minsk and the rest in other parts of the country.
It said protesters in Minsk had lit flares, erected barricades and thrown objects at police.
At least 50 civilians and 39 police officers were injured in clashes in the capital, it said, denying there were any deaths.
But a prominent rights group differed on Monday.
The Viasna Human Rights Centre said a young male protester suffered a traumatic head injury when he was hit by a police vehicle and medics were unable to save him.
Viasna representative Sergey Sys said more than 300 people had been arrested on Sunday, including more than 150 in the capital Minsk.
"Dozens of people were wounded as a result of clashes with law enforcement agencies.
Ten of them were taken to hospitals," he said.
Belarus, a country of 9.5 million people, has reported more than 68,500 coronavirus cases and 580 deaths but critics have accused authorities of manipulating the figures to downplay the death toll.
Lukashenko has dismissed the virus as “psychosis” and declined to apply measures to stop its spread, saying a lockdown would have doomed the already weak economy. He announced last month that he had been infected but had no symptoms and recovered quickly, allegedly thanks to playing sports.