Belarusian opposition leader Svetlana Tikhanovskaya in an interview with AFP called on Russia to "listen to the people" after protests over the jailing of Kremlin critic Alexei Navalny.
Tikhanovskaya, whose husband was imprisoned in Belarus last year after trying to register as a presidential candidate, also drew a parallel between her fate and that of Navalny's wife Yulia.
She urged her to "hold on, fight and have faith".
"When they imprison our husbands for their campaigning and their desire to improve life in our countries, we wives can only stand in their place and support them how we can," she said.
She said Russia's leadership should "above all listen to the people, to their demands, find out what's wrong and try to resolve this in a civilised way, without batons or stun guns".
The imprisonment of Navalny, a campaigner who has accused President Vladimir Putin of corruption, has led to a wave of protests across Russia that have been harshly put down by the authorities.
Putin is a close ally of Belarusian President Alexander Lukashenko, an authoritarian leader who was re-elected for a sixth time last year in an election that the EU considers illegitimate.
Tikhanovskaya, who also claimed victory in that vote, fled to neighbouring Lithuania amid a bloody crackdown on mass demonstrations against Lukashenko.
- 'The regime will collapse' -
Speaking ahead of the six-month anniversary of the start of the demonstrations in her own country, Tikhanovskaya said there was evidence that Belarus's political system "is shaking".
"The regime will collapse from within," she said, pointing in particular to a growing number of law enforcement officials leaking information about alleged human rights violations by police.
"It won't happen by magic. Belarusians have to do this step by step, constantly keep up the pressure... It is the only way," she said.
She also repeated her calls for additional "heavy and wide-ranging" EU sanctions on Belarus, saying that existing ones had been "very measured and this has disappointed many Belarusians".
Tikhanovskaya and her team have set up an online public database for recording possible human rights violations by Belarusian authorities that she hopes will eventually lead to prosecutions.
EU member Lithuania has already begun an investigation under universal jurisdiction and Tikhanovskaya said she hoped more countries would follow suit.
"You can help by showing the regime that we are watching, we are monitoring, we are exercising pressure on this lawlessness," she said.
Tikhanovskaya is calling for new elections in Belarus in which Lukashenko, who has been in power since 1994, would not be allowed to stand.
Lukashenko has ruled out fresh elections.
- 'He has faith in me' -
The 38-year-old mother of two, who only stood for election when her husband was prevented from doing so, has previously ruled out standing in any fresh elections, but now says it is possible.
"If I am needed at that moment, if I am useful to Belarusians as a politician, a young one, then of course I will be there.
"But if I understand that everything is in safe hands... I would go back to a normal life with a clear conscience with my children and my husband."
For now, her husband Sergei, a popular blogger, remains in prison on charges of organising unrest and the two have to communicate through a lawyer.
"We can't call or see each other, we just send each other letters" carried by the lawyer.
"It's been eight months so of course he's tired... But he's holding up. He has faith in Belarusians and he has faith in me."