Belarus opposition leader Svetlana Tikhanovskaya has vowed to "stand till the end" in protests over disputed elections and subsequent violence.
She told the BBC that if the protest movement stepped back now, they would be "slaves".
Protests and strikes continue, but President Alexander Lukashenko shows no sign of backing down nearly two weeks after the election was held.
He has vowed to crush the unrest in the coming days.
Ms Tikhanovskaya stood as the main opposition candidate, drawing large crowds during the election campaign.
But she left for neighbouring Lithuania a day after the 9 August election, saying she feared for her family's safety, after Mr Lukashenko was officially declared the winner by a landslide. She has said she will go back when she feels safe.
The results prompted widespread unrest and a brutal police crackdown, which only led to more protests.
Last weekend an estimated 200,000 anti-Lukashenko protesters filled central Minsk, and mass strikes are continuing.
Belarus - the basic facts
Where is Belarus? It has Russia - its former imperial master - to the east and Ukraine to the south. To the north and west lie EU and Nato members Latvia, Lithuania and Poland.
Why does it matter? Like Ukraine, this nation of 9.5 million is caught in rivalry between the West and Russia. President Lukashenko, an ally of Russia, has been nicknamed "Europe's last dictator". He has been in power for 26 years, keeping much of the economy in state hands, and using censorship and police crackdowns against opponents.
What's going on there? Now there is a huge opposition movement, demanding new, democratic leadership and economic reform. They say Mr Lukashenko rigged the 9 August election - officially he won by a landslide. His supporters say his toughness has kept the country stable.
'If not now, we'll be slaves'
Ms Tikhanovskaya told the BBC Belarusians had voted for her, not as a future president but as a "symbol of changes".
"They were shouting for their future, for their wish to live in a free country, against violence, for their rights," she said, in her only interview with a Western media outlet.
Despite the fact that the protests had stalled, they had to go on, she added.
"We have no right to step back now - if not now, we'll be slaves and our people understand this and I'm sure we will stand till the end."
Earlier in a video address, Ms Tikhanovskaya urged supporters to step up strikes despite "intimidation" from the authorities.
There have been reports of pressure put on strikers as Mr Lukashenko tries to reassert control.
The president insisted that the crisis would soon be over.
"This is my problem, which I should resolve, and we are resolving it," he said in a visit to a state food factory. "And believe me, in the coming days it will be resolved."
Meanwhile allies of Ms Tikhanovskaya on the new opposition Co-ordination Council have been summoned to the Belarus Investigative Committee (SK), as they are now accused of an illegal power grab.
A lawyer for the council, Maxim Znak, and Sergei Dylevsky, organiser of strikes at the Minsk Tractor Factory, were questioned on Friday.
The council, which also includes prominent Belarusian cultural figures, was launched to organise a peaceful transition and pave the way for a re-run of the election.
But on Thursday the chief prosecutor launched a criminal case against the council, calling it unconstitutional. President Lukashenko has called some of the protesters "Nazis".
Maxim Znak told the BBC he was concerned he could be arrested on Friday.
Traditionally loyal factory workers at state enterprises joined the strike action, in an unprecedented show of defiance towards Mr Lukashenko.
But reports say the number of strikers has fallen because of the official pressure on them. For example, those who walked out of state TV were told they would not get their jobs back.
Police intervened in a demonstration outside the Minsk Tractor Factory, arresting protesters.
EU leaders and the US government see Mr Lukashenko's victory as fraudulent and back the opposition's demand for an election re-run.
Russian President Vladimir Putin discussed the Belarus crisis on Friday with his security chiefs.
A Kremlin statement later said "they stressed that any outside interference in the republic's affairs is unacceptable and that the only way to settle all of Belarus's internal problems is through dialogue between the country's leadership and its citizens".
Ms Tikhanovskaya has appealed to European leaders to help establish such a dialogue. Meanwhile, the EU has announced sanctions against Mr Lukashenko.