Images from the scene of the Tupolev Tu-154M crash in Mashhad show that both wings and the empennage from the aircraft were torn off in the accident.
The jet's nose carries the name 'Surgut' in Cyrillic, identifying it as the Kolavia aircraft registered RA-85787, although it was operating for Iran's Taban Air.
While the time of the accident has not been confirmed, meteorological data from Mashhad Airport shows it was experiencing fog at around 06:00.
NOTAM information for Mashhad states that runway 13L/31R and taxiway F have been closed "due to disabled aircraft".
Iran's Civil Aviation Organisation is cited by the country's state media as saying that the aircraft - en route from Isfahan to Mashhad - had declared a medical emergency on board before the accident.