Another Belarus opposition figure was seized on Wednesday (September 9).
Maxim Znak was detained by masked men wearing plain clothes, according to his supporters.
He was taken two days after another opposition leader, Maria Kolesnikova was snatched in the street - also by masked men.
She thwarted an attempt to deport her by tearing up her passport to avoid being forced to cross the border into Ukraine on Tuesday (Sepetember 8), according to two of her allies.
She remains in detention, but her whereabouts are unknown.
Znak's detainment comes as authorities extended a systematic campaign to round up the leaders of a month-long protest movement.
Both he, and Kolesnikova, are prominent leaders of demonstrations - which demand the resignation of President Alexander Lukashenko, following an August 9th election that the opposition says was rigged.
Znak was the last member of the opposition's Coordination Council still active inside Belarus, apart from Nobel prize-winning author Svetlana Alexievich, who has served as a figurehead for the movement.
On Wednesday, she accused the Belarus authorities of terrorizing their own people - and demanded Znak's immediate release.
She had summoned supporters to her home after being harassed by repeated phone calls from unknown numbers - and constant ringing at her door by strangers.
The rest of the Coordination Council members have either fled, been forced abroad or been detained in a crackdown by Lukashenko’s security forces, as he seeks to maintain his 26-year grip on power in the former Soviet republic.
On Tuesday, he said that without his rule, Belarus would collapse.
And on Wednesday, he blamed the protests on 'foreign interference'.
Another exiled Belarusian opposition leader Sviatlana Tsikhanouskaya, who was Lukashenko's main opponent during the election, said on Wednesday that anti-government demonstrations in her country should remain peaceful.
She spoke during a visit to the Polish capital of Warsaw.
Poland, along with Lithuania and Latvia, has sought to "set an example" for the European Union by offering extensive financial and social support to Belarus' opposition movement.