The pilots of the Boeing-727, operated by Iran's national airline and carrying 104 passengers and crew, reported a technical failure to the control tower before trying to make the landing Sunday night, state-run TV reported. The IranAir aircraft broke into several pieces, but Mahmoud Mozaffar, head of the rescue department of Iran's Red Crescent Society, said there was no explosion or fire.
Footage on state TV showed the plane's crumpled fuselage lying in a field, torn apart in several places, under whirling snow in the darkness as rescue workers and local farmers searched for survivors in the hours after the crash.
Heavy snow hampered rescue efforts, the semiofficial Fars news agency cited the head of the state emergency center, Gholam Reza Masoumi, as saying. That report also mentioned fog in the area.
State TV said the aircraft disappeared from radar and went down in farmland after making a second attempt to land at the airport in the northwestern city of Orumiyeh. The nature of the technical failure was not clear.
Iran's Transport Minister Hamid Behbahani said 77 people died and 27 were injured, some critically. Behbahani said the flight was carrying 104 passengers and crew, correcting earlier reports of 105 on board. The state news agency IRNA said two children were among the dead.
Behbahani said the plane's flight data recorder, known as the black box, has been recovered "and is now being studied by a committee probing the crash."
Some of the passengers were able to walk away from the landing, said Abbas Mosayebi, a spokesman for the civil aviation authority. There were conflicting accounts on whether all 104 on board were accounted for, with some TV reports saying all were found and others saying two remained missing.
President Mahmoud Ahmadinejad sent a message of condolence to the families of the victims and ordered a quick investigation of the cause of the crash.
The aircraft was headed from Tehran to Orumiyeh, capital of West Azerbaijan province, a distance of about 460 miles, or 700 kilometers.
Iran has a history of frequent air accidents blamed on its aging aircraft and poor maintenance. Many of the Boeing aircraft in IranAir's fleet were bought before the country's 1979 Islamic Revolution, which disrupted ties with the U.S. and Europe.
Iranian airlines, including those run by the state, are chronically strapped for cash, and maintenance has suffered, experts say. U.S. sanctions prevent Iran from updating its 30-year-old American aircraft and make it difficult to get European spare parts or planes as well. The country has come to rely on Russian aircraft, many of them Soviet-era planes that are harder to get parts for since the Soviet Union's fall.
In July 2009 a Russian-made jetliner crashed in northwest Iran shortly after taking off from the capital, killing all 168 on board.
In February 2003 a Russian-made Ilyushin 76 carrying members of the Revolutionary Guard crashed in the mountains of southeastern Iran, killing 302 people aboard.