Belarusian opposition politician Svetlana Tikhanouskaya says she refuses to recognise official results that show incumbent Alexander Lukashenko has won a landslide re-election victory.
Preliminary official results on Monday showed Lukashenko won 80 per cent of the vote in Sunday's election.
Tikhanouskaya, a former English teacher who emerged from obscurity to become his main rival, won 9.9 per cent 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.
Foreign observers have not judged an election to be free and fair in Belarus since 1995, and the run-up to the vote saw authorities jail Lukashenko's rivals and open criminal investigations into others who voiced opposition.
A former Soviet collective farm manager, Lukashenko has ruled the country since 1994, but is facing his biggest challenge in years to keep his grip on power amid disenchantment in some quarters over his handling of the COVID-19 pandemic, the economy and his patchy human rights record.
The streets were quiet in the capital Minsk and other cities after violence on Sunday night when police used force to try to disperse thousands of protesters who gathered after polls closed to denounce what they said were illegitimate elections.
Protesters clapped, shouted "victory", waved flags and honked car horns in solidarity with the opposition. Some built barricades with garbage cans. Police fired water cannons, tear gas and stun grenades to try to force people to go home.
Video footage showed helmeted police forcefully detaining protesters and a police van hit a crowd of people in Minsk, witnesses said.
Spring 96, a rights group, said at least one person had been killed in the van incident. It said dozens had been injured in the clashes and that over 100 people had been detained.
Authorities said nobody had lost their life in the violence, but that 10 police officers had been injured.
Tikhanouskaya entered the race after her blogger husband who intended to run was jailed.
On Sunday, she called on her supporters to prevent what she called provocations and for authorities to refrain from violence. Her rallies have drawn some of the biggest crowds since the fall of the Soviet Union in 1991.
Lukashenko's attempts to crack down on protests could hurt his wider effort to mend fences with the West amid fraying ties with traditional ally Russia, which has tried to press Belarus into closer economic and political union.
Human rights groups say more than 1300 people were detained in the crackdown ahead of the election, including independent election observers and members of Tikhanouskaya's campaign team.
After casting his vote on Sunday, Lukashenko denied imposing repressive measures as "fake news or far-fetched accusations".
Australian Associated Press