Iran called on all parties involved, including the American Boeing Corporation, to take part in an investigation into the crash of a Ukrainian plane near Tehran, leaving 176 people killed, Press TV reported.

According to international rules, representatives of the civil aviation agency of the country where the accident occurred, the civil aviation agency of the country that issued the certificate of airworthiness, the owner of the airliner, the manufacturer of aircraft and the manufacturer of jet engines may be involved in the investigation process. Representatives of Ukraine are already in Iran, said Ali Rabiei, representative of the Iranian administration.

Rabiei denied Pentagon allegations that the plane could have been shot down by a rocket. He called these allegations a psychological government operation that offends the families of the victims. Meanwhile, IIranian Foreign Ministry spokesman Abbas Mousavi said Iran had launched an investigation into the causes of the crash in accordance with international principles and principles of the International Civil Aviation Organization (ICAO). Mousavi noted that Iran sent invitations to Ukraine and Boeing Co. to participate in the investigation.

“Scientifically, it is impossible that a missile hit the Ukrainian plane, and such rumors are illogical,” ISNA quoted Ali Abedzadeh as saying.

US officials said Thursday the plane could most likely been brought down accidentally by Iranian air defenses, Reuters reported.