A passenger SSJ-100 plane flying from Budapest to Moscow has squawked a Code 7700 distress signal indicating an emergency, according to Flightradar24.
The portal said that the plane sounded the alarm for six minutes before descending from 35,000 to 15,000 feet. The jet is now maintaining a 15,000-foot altitude.
The aircraft was scheduled to land at Sheremetyevo Airport in Moscow at 14:53 local time.