Iranian officials say as many as 118 people are feared dead following the crash of a passenger jet on a flight from Tehran.
Iran Air Tours Flight 956 took off from Tehran Mehrabad Airport on a domestic flight to Khorramabad. But 25 kilometers west of Khorramabad, the plane crashed into snow covered mountains.
Villagers living near the crash site along the Iraqi border reportedly heard a large explosion and saw fire after the Russian-made Tupolev TU-154 went down.
A spokesman for the Civil Aviation Organization of Iran, Reza Jaafarzadeh, said everyone on board the plane is feared dead.
Search and rescue teams have been dispatched to the area, but heavy snow is said to be hampering their efforts.
Relatives and friends gathered at the Tehran airport seeking information about their loved ones.
Iran's state-run television reported President Mohammad Khatami has ordered creation of an emergency committee to investigate the cause of the crash.
Iran Air Tours is a subsidiary of the state-run carrier Iran Air. It leases planes from former Soviet countries and uses Russian crews.
The TU-154 is the most widely used jetliner in Russia and is used in many other countries in the region. It has a seating capacity of 148 passengers. The crash was the 20th involving a TU-154 since the jetliner entered service in the early 1970s.
Iran has an aging fleet of U.S.-made Boeing aircraft purchased before the 1979 Islamic revolution. The U.S. has refused to provide Iran with spare parts as part of its economic sanctions against Iran. In recent years, Iran has purchased a small number of Airbus passenger planes.