Ukraine's SBU State Security Service acting under the procedural guidance of the military prosecutor's office in Mariupol has detained a man who, as part of a criminal group, was preparing terrorist attacks and riots in Ukraine during the presidential election in coordination with Russia's FSB Federal Security Service.

"It has been established that citizen K. acted on preliminary agreement with currently unidentified persons and coordinated his actions with FSB officers deployed in Russia-annexed Crimea. The goal of his activities was to forcibly support opposition political associations through the commission of terrorist acts and riots in Ukraine during Ukraine's presidential elections," the press center of the Joint Forces Operation (JFO) said on Facebook on Thursday.

During August 2018 - January 2019, SBU agents documented the acquisition by citizen K. of military grenades and 11 Makarov pistols for a total of $5,250, the sale of narcotics (amphetamine) weighing 11 grams for a total of UAH 5,000 and a $600 payment to an investigator for causing serious injury to a third party.

"On January 10, 2019, citizen K. was detained while purchasing another batch of firearms – three Makarov pistols," the SBU said.

Priority investigative (search) actions are being carried out, as well as searches at the suspect's work place and residence.

Law-enforcement agencies are currently deciding what crimes to charge the man with and recommendations for his preventative custody.