Iran's civil aviation organization has grounded ATR-72 planes belonging to Aseman Airlines after one of them crashed this week with 65 people on board, state media reported on February 23.
The regulator was reported as saying that the measure was temporary as authorities investigate the cause of the accident on February 18 in which an ATR-72 twin-engine plane that had been in service since 1993 crashed in Iran's Zagros mountains.
"In order to make sure of the improvement of this type of aircraft's safety, it is necessary to stop their flights temporarily," IRNA news agency quoted the regulator as saying.
Aseman, which is banned from flying in the European Union, operates five ATR-72s, according to the company's website.
Flight EP3704 disappeared from radar around 45 minutes after taking off from Tehran on a domestic flight. No survivors have been found. The flight was carrying 59 passengers and six crew members.
The wreckage of the ATR, which is part-owned by Europe's Airbus, was discovered at a height of around 4,000 meters (13,000 feet) in the Dena range, but bad weather has hampered recovery efforts.
Helicopters have been unable to access the site and an operation to bring bodies down the mountain on foot has been suspended until February 26.
The plane's "black box" flight recorders have also not yet been recovered.
Under decades of international sanctions, Iran's commercial passenger aircraft fleet has aged, with air accidents occurring regularly in recent years.