Flights from Ulaanbaatar to Irkutsk?

Do flights still exist between Ulaanbaatar, Mongolia and Irkutsk, Russia? I may need to take one this winter instead of going overland by bus/train via Ulan Ude, Russia (2 days train/bus travel versus an hour or so flight). Several reputable sources claim they do (as low as $60-70 one-way in the winter) but the Mongolian Airlines website does not show the route available. I also checked the websites of Aeroflot and some Russian airlines that operate in Siberia.

Thank you for this, I appreciate this information.