Authorities in Iran have suspended efforts to reach the site of a crashed passenger airliner because of high winds, snow, and darkness.
All 65 people aboard the plane are feared dead after the aircraft crashed in a mountainous area of the central province of Isfahan earlier on February 18.
The plane came down in the Zagros mountains near the city of Semirom while flying between Tehran's Mehrabad airport and the southwestern city of Yasuj, the national emergency services said on February 18.
The plane was said to be a twin-engine turbo prop ATR 72 operated by Iran's Aseman Airlines.
The plane was carrying 59 passengers, four crew members, and two air marshals. Earlier reports said the plane had 60 passengers, but Iranian officials later said one ticketed passenger missed the flight.
Airline spokesman Mohammad Taghi Tabatabai told state TV that the plane crashed into Mount Dena, which is about 440-meters high, and that all on board the flight were killed in the accident.
However, he later told the ISNA news agency, "We still have no access to the spot of the crash and therefore we cannot accurately and definitely confirm the death of all passengers of this plane."
The plane was carrying 60 passengers and six crew members.
It was not immediately clear what caused the crash.
The Iranian Red Crescent said it had dispatched 12 rescue teams to the area.
Foggy weather has prevented a rescue helicopter from reaching the crash site, state TV reported.
"Given the fact that the area is mountainous, it is not possible to send ambulances," said Mojtaba Khaledi, spokesman for the national emergency services.
Semirom lies around 480 kilometers south of the capital, Tehran.
European airplane manufacturer ATR said it had no immediate information about the crash.
Aseman Airlines, headquartered in Tehran, is Iran's third largest airline. It specializes in flights to remote airfields across the country but also flies internationally.
Decades of international sanctions have left Iran with an ageing commercial passenger aircraft fleet that it has struggled to maintain and modernize.
Only after Tehran signed a landmark nuclear deal with world powers in 2015 could it order new planes from Airbus, ATR, and Boeing. About a dozen of the new planes have been delivered so far.