A Russian airline UTair Boeing 737 plane, carrying 78 passengers plus crew, requested an emergency landing at the main airport in St. Petersburg, the company and a Russian aviation source said.
The source said one of the plane's engines had failed and that the plane had been due to land at 12:25 p.m. (09.25 GMT). Russia's Emergencies Ministry said it could not immediately comment.
FlightRadar said the plane has successfully landed at the airport in St Petersburg with just one engine.
The emergency landing was carried out 'after the transmitter went off, signalling the right engine's failure', a source told RIA Novosti news agency.