Belarus presidential challenger Svetlana Tikhanovskaya said in a video Tuesday that she had left her country for Lithuania.
"I have made a very difficult decision," a distressed-looking Tikhanovskaya said in a short address carried by tut.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."
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 added. "What is happening now is not worth a single life."
On Monday, Tikhanovskaya claimed victory over the authoritarian Lukashenko in Sunday's vote and urged the 65-year-old strongman to hand over power peacefully.
She decided to run for president after the authorities jailed her husband, popular blogger Sergei Tikhanovsky, and barred him from contesting.
Her campaign galvanized 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".
Many Belarusians say Lukashenko has stolen the election from Tikhanovskaya, and thousands took to the streets in the capital Minsk and other cities on Sunday and Monday. Dozens of people were injured and police said that one man died in the protests Monday night.
President Gitanas Nauseda's office said Tikhanovskaya was "resting" in the Baltic state.
"The president's office is in constant contact with Svetlana Tikhanovskaya, who arrived in Lithuania. She is currently resting," Nauseda's spokesman Antanas Bubnelis told AFP.
Lithuanian Foreign Minister Linas Linkevicius told AFP earlier Tuesday that Tikhanovskaya had "arrived in Lithuania and is safe."
Tikhanovskaya's whereabouts had been unknown as of late Monday in Minsk.
EU and NATO member Lithuania, which was also once part of the Soviet Union, has a history of granting refuge to Belarusian and Russian opposition figures.
Poland's foreign minister said Tuesday his nation is willing to mediate the dispute between Tikhanovskaya and Lukashenko.