Three of the Belarusian opposition’s top organizers were reported missing Monday (September 7), the day after tens of thousands joined protests in the country’s capital of Minsk that kept up the pressure on President Alexander Lukashenko to hold new elections, as seen in this footage here.

“Peaceful actions all across Belarus since Aug. 9 and representing the view of the majority of people are so massive that authorities have begun actively to use methods of terror in order to suppress them,” the united opposition’s coordinating council said on its website Monday.

Kolesnikova, one of the few leading opposition figures still in Belarus, was allegedly abducted but is said to now be in Ukraine, after crossing the border in the early hours of September 8.

The council’s spokesman Anton Radniankou and its executive secretary Ivan Krautsou have been “kidnapped” by unknown people, according to the statement.

Amid a renewed police crackdown on protesters, detentions and the forced expulsion from Belarus of another council member, Volha Kavalkova, the disappearances may deepen the crisis in the country, the council warned.