ROSTOV-ON-DON, August 21. /TASS/. Rostov Region Governor Vasily Golubev explained the loud noise heard by residents of Rostov-on-Don and its surroundings by the transition of an airplane to supersonic speed.

"In connection with numerous reports of loud sounds that were heard in various parts of Rostov-on-Don and the surrounding areas. The military informed about the transition of the aircraft to supersonic speed," he wrote on his Telegram channel.

The head of the region urged everyone to remain calm.