The helicopter crash, which killed several senior Iranian officials, was mainly due to weather conditions, including thick fog, the final investigation report said, Iranian state television reported, Reuters reported, citing from BTA.
The incident, which killed several people, including high-ranking officials, took place in a mountainous area near the border with Azerbaijan.
"The main cause of the helicopter crash was the complex weather conditions in the region," said the final report.
A dense mass of fog caused the helicopter carrying the victims to crash into the mountain, according to the report drawn up by a commission tasked by the Iranian military with investigating the incident.
A preliminary report by the Iranian military in May said the investigation found no evidence of wrongdoing or an attack on the flight.