Opposition leader Maria Kolesnikova, who is one of the trio of women who campaigned against Belarus' self-appointed president Alexander Lukashenko in the August 9 presidential election, has gone missing.

Kolesnikova was bundled into a van marked “Connections” (a word associated with telecoms in Russian) near the National Art Theatre in central Minsk at about 10am on the morning of September 7 by a group of masked unidentified men, which then drove away to an undisclosed destination.

Her colleagues claim she was abducted by the authorities, although the Ministry of the Interior denied Kolesnikova had been arrested in comments to the  Russian news agency RIA Novosti.

“I walked forward and heard the sound of a phone falling on the asphalt, some kind of stamping, turned around and saw that people in civilian clothes and in masks were pushing Maria [Kolesnikova] into this minibus. Her phone fell and one of the men picked up the phone, jumps into the minibus and they left,” an eyewitness Anastasia told the Tut.by news outlet.

Journalists at Tut.by called Kolesnikova's phone, which was working, but no one picked up.

Another two members of her team (pictured) that organised the election campaign for jailed ex-banker and leading opposition candidate Viktor Babariko have also disappeared. None of them are answering their phones, according to reports on social media.

Kolesnikova is the only one of the trio, also made up of Svetlana Tikhanovskaya and Veronika Tsepkalo, who is still in Belarus. She has been a prominent face at the weekly mass rallies and a leading figure at the women-only rallies that have been held on the last two Saturdays.

Kolesnikova is also a member of the newly established Coordinating Council that is calling for talks with the state on forming a transition government and holding fresh elections. Lukashenko has refused to recognise the Coordinating Council and the prosecutors office has opened dozens of cases against the committee, accusing it of attempting to organise a coup d'état.

The spokesman for the Coordination Council Anton Rodnenkov told Tut.by at 10:13 that Maria was alone in the city centre on business. Rodnenkov learned about her disappearance from Tut.by and began to search for her as well.

Kolesnikova also last week announced that she and Babariko were setting up a new political party called “Together” to contest elections and represent opposition interests in parliament.

Lukashenko has been slowly ramping up pressure on the protest movement. Another mass rally was held on September 6 with somewhere between 100,000 and 250,000 people in attendance. However, at this latest rally, that met under the slogan “unity”, the police presence was higher than at the previous rally and unmarked vans have been patrolling Minsk, randomly snatching pedestrians from the street.

NGOs reported that 633 people were detained over the weekend in the latest sign that Lukashenko is attempting to slowly turn the screw on the protest movement.