Mass protests erupted against President Alexander Lukashenko last summer after he declared victory in a presidential election that his opponents said was rigged, but they lost momentum amid a sweeping crackdown by the authorities.
Lukashenko said in televised comments on Wednesday that he believed there would be no repeat of the mass protests that erupted last summer. His comments came shortly after the statement by the opposition.
"There's nothing more to wait for. Terror must be stopped once and for all," opposition politician Pavel Latushko said on social media.
Exiled opposition leader Sviatlana Tsikhanouskaya added "We must be ready to act. The window of opportunity is open."
Lukashenko's decision to intercept an international airliner flying through his country's air space and arrest a 26-year-old dissident journalist has brought a new level of condemnation.