"The wreckage from the crashed Tehran-Yasuj plane was found a few minutes ago," Fars news agency quoted Mojtaba Moradi at the governor's office of Kohgiluyeh and Boyer-Ahmad province as saying.
He said the wreckage was found in an area in Noqol and Dengezlu village in Semirom which is part of the central Isfahan province.
It came on the second day of search for the ATR-72 plane which crashed in bad weather Sunday morning. As many as 26 teams of mountain climbers were scouring valleys, slopes and ridges on Monday.
The Aseman Airlines plane, a twin-engine turboprop used for short-haul regional flight, was traveling from the capital Tehran to the southwestern city of Yasuj.
The plane disappeared from radar screens 50 minutes after taking off from Mehrabad airport which mainly handles domestic flights.
A relative improvement in weather conditions on Monday allowed helicopters and drones to fly over the extremely mountainous area which features some 100 peaks higher than 4,000 meters (13,000 feet).
Air controllers say the pilot had not reported any problems in his last contact with the tower 14 miles from the airport. According to airplane-tracking website FlightRadar24, the plane’s last signal at 0555 GMT showed it at 16,975 feet and descending.
Emergency workers had to get to the remote area by land amid dense fog, high winds and heavy snow which hampered search and rescue operations.
Leader, president offer condolences
On Sunday, Leader of the Islamic Revolution Ayatollah Seyyed Ali Khamenei and President Hassan Rouhani expressed sympathy with the bereaved families and offered their condolences to the people of Iran.
Ayatollah Khamenei said the news had “left our hearts overwhelmed with sadness and sorrow”.
The Leader urged authorities to exert all efforts required by them in the aftermath of the accident, and ensure the honorable interment of the victims.
Rouhani ordered the Transport Ministry to set up a crisis group to investigate the crash and coordinate efforts.
A man who missed the doomed flight told reporters of his mixed emotions.
"God has been really kind to me but I am so sad from the bottom of my heart for all those dear ones who lost their lives," said the unnamed man.
Decades of sanctions have left Iran's airlines with ageing fleet of passenger planes which they have struggled to maintain and modernize.
Aseman Airlines, owned by Iran's civil service pension foundation, is a semi-private air carrier headquartered in Tehran that specializes in flights to remote airfields across the country. It also flies internationally. It is Iran's third-largest airline by fleet size, behind state carrier Iran Air and Mahan Air.
The carrier has a fleet of 29 aircraft, including six ATR aircraft, according to FlightRadar24, a plane-tracking website. The ATR-72 that crashed Sunday had been built in 1993, Aseman Airlines CEO Ali Abedzadeh said.
A spokesman for ATR, which is part-owned by Europe's Airbus, told AFP the company was "researching the details" of Sunday's crash.
Aseman Airlines has suffered other major crashes with fatalities. In October 1994, a twin-propeller Fokker F-28 1000 commuter plane flown by the airline crashed near Natanz, 290 kilometers (180 miles) south of Tehran, also killing 66 people on board. An Aseman Airlines chartered flight in August 2008, flown by an Itek Air Boeing 737, crashed in Kyrgyzstan, killing 74 people.
Iran has suffered multiple aviation disasters, most recently in 2014 when a Sepahan Airlines plane crashed killing 39 people just after takeoff from Tehran, narrowly avoiding many more deaths when it plummeted near a busy market.
Lifting sanctions on aviation purchases was a key clause in the nuclear deal Iran signed with world powers in 2015.
In April 2017, ATR sealed a $536-million sale with Iran Air for at least 20 aircraft. Chicago-based Boeing also signed a three-billion-dollar deal that month to sell 30 737 MAX aircraft to Aseman Airlines with an option to buy 30 more.
However, the sale could be scuppered if US President Donald Trump chooses to reimpose sanctions in the coming months, as he has threatened to do.
The US Treasury Department, which must approve aviation sales to Iran, has done so for 80 Boeing jets destined for national carrier Iran Air as well as 100 Airbus planes for Iran Air.
The first few Airbus jets have already arrived in Tehran.
AFP, AP and Press TV contributed to this story.