The airline told Iranian media that all 60 passengers and six crew members on the ATR 72 twin-engine turboprop plane were killed.
Witnesses on the site of the crash revealed to local media that it appeared the aircraft was trying to make an emergency landing on a pasture before it crashed about 15 miles from its destination.
The crash site is near Semirom in Isfahan province, about 300 miles south of Tehran, but a helicopter carrying rescuers was unable to immediately land due to severe weather.
The plane took off from Tehran’s Mehrabad Airport at about 8am local time on a roughly 90-minute journey to Yasuj, but soon disappeared from radar screens, sparking a wide search.
It was later confirmed by the airline that there was no survivor in the crash. All the passengers including the crew members, which include two pilots, two flight attendants and two security officers lost their lives.
Iranian media published photos of the pilots, including the experienced captain, and the security guards, as well as a passenger list.
Reports said the pilot of the doomed plane was involved in at least one earlier emergency, when he managed to land an aircraft at Yasuj airport following an engine failure in 2013.
Families of the victims of the crash were seen at the airport in Yasuj waiting for updates on the development of the incident.