The number of deaths is expected to increase as many of the injured were in serious condition [Reuters/IRNA]

Up to 70 people on board an IranAir passenger jet have been killed and more than 30 injured after it crashed in the country's northwest, IRNA, the Iranian news agency, says quoting an Iranian Red Crescent official.

The aircraft crashed near Orumiyeh at around 16:15 GMT on Sunday, an official in West Azerbaijan province was quoted by state television's website as saying.

"The airplane took off an hour later than scheduled time from Tehran towards Orumiyeh and because of bad weather conditions came down in a village area near Orumiyeh," the unidentified official said.

Al Jazeera's Alireza Ronaghi, reporting from Tehran, said that roughly 70cm of snow has blanketed the ground in the Orumiyeh, around 700km north of Tehran.

"This plane has been one of these very old kind of aircraft that are still serving in Iran's airlines - a Boeing 727, which is more than 40 years old," he said.

The US-made aircraft has been out of production since 1984.

The semi-official Fars news agency initially reported that 105 people were believed to be on board, but an official statement said that there were 95 passengers and eight crew members in total.

Shahrokh Nioushabadi, a spokesman for IranAir, told the semi-official Mehr news agency that two children were among the passengers.

The Iranian Red Crescent said many of the injured passengers were in serious condition, and the number of deaths is likely to increase.

State television showed footage of the wreckage of the plane, which appeared to have broken into several sections on impact. Huge gaps were rent in the fuselage, parts of which were open to the night air as snow fell.

Passenger plane crashes are not uncommon in Iran, where sanctions have prevented Iran from purchasing parts for its commercial fleet.

The last major air crash in Iran was in July 2009 when a Caspian Airlines Tupolev aircraft bound for Armenia caught fire in mid-air and crashed into farmland near the city of Qazvin, killing all 168 people on board.

One of the country's worst air accidents happened in February 2003 when an Iranian Ilyushin-76 troop carrier crashed in southeast Iran, killing all 276 Revolutionary Guard soldiers and crew aboard.