At least 77 people are confirmed to have died after a commercial IranAir passenger jet crashed in the country's north.
Mahmoud Ahmadinejad, the Iranian president, has ordered an inquiry into the crash, and investigators have now recovered the flight recorders from the wreckage of the Boeing 727.
Early reports indicate that the pilots had reported a problem with the aircraft just before losing radio contact.
Al Jazeera's Alireza Ronaghi in Tehran reported that bitter cold and roughly 70cm of snow have hampered rescue efforts.
The aircraft crashed at around 16:15 GMT on Sunday evening, and was bound from Tehran towards Orumiyeh, officials said.
Al Jazeera's Caroline Malone reports.
Source: Al Jazeera