MOSCOW, March 3. /TASS/. The blast in the Moscow region’s city of Kolomna occurred in the air and might have been caused by a drone, its fragments have not yet been found, a spokesman for the law enforcement agencies told TASS on Friday.

"The explosion occurred in the air. With a high degree of probability, it was a drone. However, one cannot be sure of that, since no fragments have yet been found," the spokesman said.

Law enforcement and emergencies officers were engaged on Thursday evening to probe into reports about an explosion in Kolomna. According to witnesses, a loud whiz was heard before the blast, which was followed by smoke and glow.

Later, emergencies services told TASS that a survey of potential facilities had revealed no signs of explosion. According to the Moscow region’s energy ministry, the city’ gas and electricity supplies facilities are operating routinely, with no malfunctions detencted.