Belarusian opposition leader Svetlana Tikhanovskaya has said she had taken a "very difficult decision" to leave the country, after disputing an election she claimed was rigged.
as the country braced a second night of protests against President Alexander Lukashenko, Tikhanovskaya said she considered herself the winner, not Lukashenko.
“The authorities should think about how to peacefully hand over power to us. I consider myself the winner of this election," she said.
Poll results gave President Lukashenko 80% of the vote, but there have been numerous claims of fraud.
Lukashenko, who is facing the deepest crisis of his 26 years in power, has threatened to crush any illegal rallies. He claimed that the protests were being directed from abroad, singling out Poland, Britain, and the Czech Republic.
Tikhanovskaya has stopped short of joining street protests and her team released a statement on Monday evening saying they feared her appearance could lead to “provocations”.
In an emotional video address to supporters (in Russian) recorded before her departure for Lithuania and posted on YouTube, Ms Tikhanovskaya said she had overestimated her own strength.
"I thought that this campaign had really steeled me and given me so much strength that I could cope with anything," she said.
"But I guess I'm still the same weak woman that I was."
She said her decision to leave was taken "completely independently" and not influenced by anyone around her, even though many people would "condemn" or "hate" her for it.
The election campaign saw the rise of Ms Tikhanovskaya, 37, a former teacher who was 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.
President Lukashenko has dismissed Ms Tikhanovskaya as a "poor little girl", manipulated by foreign "puppet masters".
The protests have largely been decentralised, with no clear leader, although popular bloggers on social media have played an important role in their coordination.
Police detained about 3,000 people in Sunday’s bloody clashes, the Belarusian interior ministry said, with more than 2,000 of them in the country’s regions, where support for Lukashenko is higher than in the capital.