Iranian media have said as many as 77 people were killed Sunday when an Iran Air passenger plane crashed in bad weather in the country's northwest.
Authorities said Monday rescuers were still looking for at least one of the 106 people who were on board the plane when it went down.
The head of the Iranian Red Crescent, Mahmoud Mozaffar, told state television Sunday the plane crashed after attempting to make an emergency landing near the city of Urumiyeh, 700 kilometers northwest of the capital, Tehran.
Iranian officials say some passengers survived with light injuries, while others had to be hospitalized. At least 10 crew members were on board the aircraft.
Earlier, Iranian media gave different accounts of the number of people on board the Boeing 727, which Mozaffar said broke into pieces but did not explode when it crashed in farmland near Urumiyeh.
The plane was en route from Tehran when it crashed. It is not clear what caused the incident, Heavy snow and fog have hampered rescue efforts.
Iran has had a number of recent air accidents, often due to aging planes and poor maintenance. U.S. sanctions against the Islamic Republic have prevented it from buying new aircraft or spare parts from the West.