Most of the people detained during an operation conducted by Ukraine's Security Service (SBU) in Krasnohorivka, Donetsk region, have already been released, the SBU director's advisor Yuriy Tandyt has said.

"Local residents also supported the measures that needed to be taken. I can say that there is a very powerful social networking website there, a common group, which includes some 8,000 people. Most of them are true patriots of Ukraine. What we did needed to be done. Only several people remain [in detention]. Specialized preventive conversations were held with the people who were detained – more than 80 people. And a very large number of illegal items were found, including weapons kept by the people who were detained," Tandyt told the Channel 5 television station on Tuesday.

It was reported that an operation to prevent terrorist attacks was carried out in Krasnohorivka on December 10. Eighty-five people, presumably involved in the activities of the self-proclaimed Donetsk and Luhansk People's Republics were detained.