A training plane crashed in central Iran on Sunday killing five people on board, the state news agency IRNA reported.
The crash happened when the plane was approaching an airport near the city of Isfahan during training on Sunday afternoon.
Its crew of a pilot and four co-pilots were all killed, the report said, without specifying whether the aircraft was military or civilian.
It said the cause of the accident was under investigation.
Most of the Iranian military's aircraft were supplied by the United States in the days of the US-backed shah and the regime has struggled to maintain them amid successive packages of US sanctions adopted since the 1979 Islamic revolution.