KIEV, Dec. 19 – The Security Service of Ukraine has prevented a terrorist attack in the center of Kiev, an advisor to the SBU head, Markiyan Lubkivsky, has said.

"The [SBU] counterintelligence department has managed to prevent a terrible tragedy in the center of Kiev – a terrorist attack that was to be made at the last minute," he said at a briefing in Kiev on Friday.

According to Lubkivsky, Ukrainian citizen Kovalenko, a resident of Luhansk, was carrying a bomb in a bag on December 17, in the area between Ivan Franko Theater and Independence Square. The weight of the explosive in the bag was three kilograms of TNT, and if the device exploded, the blast radius would have been up to 500 meters. "There could have been mass casualties," Lubkivsky said.