The main challenger in Belarus's disputed presidential election fled to Lithuania on Tuesday after a second night of street clashes between police and opposition supporters left a protester dead.

Svetlana Tikhanovskaya, who has claimed victory over authoritarian President Alexander Lukashenko in Sunday's vote, had arrived in the neighbouring country and was safe, Lithuanian Foreign Minister Linas Linkevicius told AFP.

Tikhanovskaya later posted a video confirming the escape. 

I have made a very difficult decision," a distressed-looking Tikhanovskaya said in a short address carried by, a Belarusian media outlet. 

She indicated she had left Belarus to be with her two children, who had earlier been taken out of the authoritarian ex-Soviet country for their own safety.

"Children are the most important thing we have in life," said the 37-year-old.

"You know I thought that this campaign had really steeled me and given me the strength to endure everything," she said. 

"But I probably remained the weak woman I was at the beginning," she said. 

President Alexander Lukashenko had previously belittled women politicians, saying a woman president "would collapse, poor thing."

"I know that many will understand me, many will judge me, and many will begin to hate me," Tikhanovskaya said. "But God forbid anyone face the choice I had."

"People please take care of yourselves," she said. "What is happening now is not worth a single life."

Video: AFP

Tikhanovskaya's whereabouts had been unclear after campaign staff said they had lost contact with her and there had been concern for her safety.

Her surfacing in Lithuania came after thousands took to the streets of the capital Minsk for a second night on Monday, after authorities said longtime ruler Lukashenko had secured a sixth term with 80% of the vote.

Tikhanovskaya, a political novice who has energised the opposition, came second with 10% and protesters are backing her claim to have won the election.

For the second night in a row, police used rubber bullets, stun grenades and tear gas to disperse demonstrations, though protesters fought back with stones and fireworks and built makeshift barricades, AFP reporters, protesters and witnesses said.

"Too many people are against Lukashenko," Pavel, a 34-year-old protester, told AFP.

"Our goal is to depose Lukashenko. He is not worthy of being president."

Dozens of people have been injured in the violence and the first fatality was confirmed on Monday when police said a man died after an explosive device went off in his hand.

Tikhanovskaya's staff had said earlier that she would not join demonstrations to avoid "provocations" and it was unclear how her sudden departure would affect the opposition.

'Intimidation of opposition'

Lukashenko's opponents have been calling for running protests against his regime and there were calls for a nationwide strike.

The 37-year-old mother of two decided to run for president after the authorities jailed her husband, popular blogger Sergei Tikhanovsky, and barred him from contesting.

Her campaign galvanised the opposition, presenting a historic challenge to former collective farm director Lukashenko, who has ruled Belarus since 1994, brooking no dissent and earning the nickname of "Europe's last dictator".

Western governments have widely condemned the police crackdown, with some in the European Union suggesting it may reimpose sanctions on Lukashenko's regime that were lifted several years ago.

The White House said it was "deeply concerned" by the violence, adding that "intimidation of opposition candidates and the detention of peaceful protesters" were among numerous factors that marred the election and its aftermath.

European governments also questioned the results, with Germany voicing "strong doubts" about the conduct of the vote, France urging restraint and Poland calling for an emergency EU summit.

Russian President Vladimir Putin congratulated Lukashenko, a longtime ally, as did Chinese leader Xi Jinping.

Lukashenko was defiant on Monday, vowing he would not allow Belarus to be "torn apart" and suggesting protesters were foreign pawns.

"We recorded calls from abroad. There were calls from Poland, Britain and the Czech Republic, they were directing our - forgive me - sheep," Lukashenko said.

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