A plane that crashed in Iran with 176 people on board was trying to return to the airport when it crashed, Iranian investigators have said, ONA reports citing BBC.
The Boeing 737-800 went down just minutes after taking off from Tehran's airport, leaving no survivors.
An initial probe found the aircraft experienced a problem as it was leaving the airport zone, and was "on fire".
Earlier, Iran said it would not hand over the recovered black box flight recorders to Boeing or to the US.
Under global aviation rules Iran has the right to lead the investigation, but manufacturers are typically involved.