The main challenger to Belarus’s Alexander Lukashenko has refused to accept the president won 80% of the vote in Sunday’s election.
Svetlana Tikhanovskaya’s campaign said results published on Monday morning “completely contradict common sense”.
This follows thousands of arrests after protesters and riot police clashed in the capital Minsk and other cities.
A lack of scrutiny – no observers were present – has led to widespread fears of vote-rigging in the poll.
The vote was held amid growing frustration at Mr Lukashenko’s leadership, with opposition rallies attracting large crowds. The preceding days saw a crackdown on activists and journalists.
The president has described opposition supporters as “sheep” controlled from abroad, and vowed not to allow the country to be torn apart.
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Mr Lukashenko won 80.23% of the vote, according to a preliminary count, with Ms Tikhanovskaya receiving 9.9%.
Ms Tikhanovskaya entered the election in place of her jailed husband and went on to lead large opposition rallies.
Mr Lukashenko, 65, has been in power since 1994.
What did Ms Tikhanovskaya say?
The opposition candidate said she considered herself the winner and the authorities should think about how to peacefully hand over power.
“We have seen that the authorities are trying to hold on to their positions by force,” she said.
“No matter how much we asked authorities not to turn on their own people, we were not listened to.”
Her campaign said it would challenge “numerous falsifications” in the vote.
“The election results announced by the Central Electoral Commission do not correspond to reality and completely contradict common sense,” her spokeswoman Anna Krasulina said.
But Mr Lukashenko poured scorn on Ms Tikhanovskaya’s comments.
“So Lukashenko, who is at the top of the power structure and at the head of the state, after getting 80% of the vote must voluntarily hand over power to them,” the president said. “The orders are coming from over there [abroad].”
“Our response will be robust,” he added. “We will not allow the country to be torn apart.”
What happened in Sunday’s protests?
Demonstrators took to the streets in central Minsk as soon as voting ended. Many chanted “Get out” and other anti-government slogans.
Police used stun grenades, rubber bullets and water cannon.
Early on Monday, the Belarusian human rights group Viasna said that at least one person had died.
Social media footage showed a man who had clung to the front of a police truck lose his grip as it accelerated, hitting his head.
However, the interior ministry denied that there had been any deaths. It said 50 civilians and 39 police were injured.
Three thousand people were arrested, the ministry added. About one-third of them were in Minsk, and the rest in other cities such as Brest, Gomel and Grodno where similar protests took place.
What’s the context?
President Lukashenko was first elected in 1994.
In the last vote in 2015, he was declared winner with 83.5% of the vote. There were no serious challengers and election observers reported problems in the counting and tabulation of votes.
The campaign saw the rise of Ms Tikhanovskaya, 37, a former teacher who became a stay-at-home mother until she was thrust into the political spotlight.
After her husband was arrested and blocked from registering for the vote, she stepped in to take his place.
In the lead-up to the election she told the BBC that people in Belarus did not believe the election would be run fairly.
President Lukashenko has dismissed Ms Tikhanovskaya as a “poor little girl”, manipulated by foreign “puppet masters”.
On the eve of the election Ms Tikhanovskaya’s team said her campaign manager had been arrested and would not be released until Monday.
And on Sunday, as people voted, internet service was “significantly disrupted”, according to online monitor NetBlocks. Opposition supporters say this makes it harder for evidence of election fraud to be collected and shared.
There were already concerns over a lack of scrutiny because observers were not invited to monitor the election and more than 40% of votes were cast ahead of election.
Tens of thousands defied an escalating crackdown on the opposition last month to attend a protest in Minsk, the largest such demonstration in a decade.
Anger towards Mr Lukashenko’s government has been in part fuelled by its response to coronavirus.
The president has downplayed the outbreak, advising citizens to drink vodka and use saunas to fight the disease.
Belarus, which has a population of 9.5 million, has reported nearly 70,000 cases and almost 600 deaths.