The final investigation by the Iranian Armed Forces into the helicopter crash that claimed the lives of President Ebrahim Raisi and his companions in May says the incident was caused by weather conditions that included thick fog.

According to The Iran Project, the helicopter carrying 63-year-old Raisi, former foreign minister Hossein Amir-Abdollahian and six others came down on May 19 on a fog-shrouded mountainside in northwestern Iran. Their bodies were found the following day after a massive search operation.

The report, published by the General Staff of the Iranian Armed Forces on Sunday, ruled out sabotage or tampering as the reason behind the tragic incident, saying the "complex climatic and atmospheric conditions of the region in the spring was the main cause of the crash."

It added that "the sudden emergence of a thick mass of dense and rising fog" caused the helicopter to crash into the mountainside.

According to the report, all documents related to the helicopter's repairs and maintenance since its purchase and use before the incident were thoroughly reviewed by military and civilian experts, who announced that all the measures had been conducted under standard regulations.