KIEV, Aug. 27 – The authorities will press charges against Oleksadnr Turchynov, former Prime Minister Yulia Tymoshenko’s closest ally, opening a criminal case on Monday, Segodnia daily reported Saturday citing a senior police source.

Turchynov is the key person in charge of the Tymoshenko party campaign, and any potential imprisonment may disrupt the party’s preparation for parliamentary elections in October 2012.

Tymoshenko, the chief political rival of President Viktor Yanukovych, has been imprisoned since August 5. She is on trial for negotiating a controversial natural gas agreement with Russia in January 2009.

“I think they will not stop at Tymoshenko, and will continue to imprison more people,” Mykola Katerynchuk, the leader of the opposition European party, told Liberty Radio on Saturday.

Anatoliy Lazarev, the chief of staff at the Internal Affairs Ministry, said Thursday that Turchynov may be accused of leading a peaceful march of about 3,000 protesters on the Independence Day.

The march was stopped by massive riot police force several blocks from the original place of an opposition rally, and was later dispersed.

Meanwhile, the developments come amid controversy over actions by police that had stopped the protesters on route that had been earlier approved by court.

Also, despite earlier assurances to the contrary, police on Saturday admitted that they used a strong tear gas against the demonstrators.

Lazarev, at a press conference on Thursday, denied any allegations that police may have used tear gas against the protesters.

“Police have not used any special means,” Lazarev said. “There were instructions made prior to August 24, and decision approved that police officers will not be issued means of personal defense.”

But an investigation by Ukrayinska Pravda online newspaper discovered a picture and a video showing that a police officers has been using the tear gas against the protesters.

Confronted by the picture and the video, police had later issued a statement stipulating the tear gas had been used legally.

“The investigation showed that the police officer has acted in line with law,” Volodymyr Polishchuk, the head of public relations department at the Interior Ministry, said.

He explained that the office used the tear gas to defend a fellow police officer that had been allegedly attacked by the protesters.

But opposition leaders vowed to sue police for stopping the peaceful march on the Independence Day.

“We will get to the bottom of this and will sue the police,” Katerynchuk said. “We will bring everybody to justice.” (tl/ez)