MOSCOW, December 24. /TASS/. A passenger plane safely landed in Moscow after sending a distress signal and descending in mid-flight, a representative of air traffic services told TASS.

Officials are investigating what the reason was for the Boeing 737 plane that was heading from Saratov to Moscow to signal distress, the person said.

Meanwhile, another plane, which is performing a flight from Krasnodar to St. Petersburg, sent a distress signal, an air traffic control source told TASS. The Airbus A319 is scheduled to reach its destination in about 30 minutes, the source said.