The Ukrainian air crash case will now be investigated by the UN aviation watchdog. The plane crash in Iran had killed 176 people onboard. Heading to Ukraine capital Kiev, Ukrainian flight PS752 came down minutes after takeoff from the Tehran International Airport. Iran on Saturday admitted that it had accidentally shot down the plane shortly after striking American air bases in Iraq in response to the US drone killing of top Iranian General Qassem Soleimani.
Tehran launched an investigation into the Ukrainian plane crash and on Tuesday announced to have made the first arrests in connection with the incident.
Iran had invited the UN for support in its probe into the Ukrainian plane crash.
In a statement, the International Civil Aviation Organization (ICAO) said that the invitation from Iran was accepted on Tuesday.
The ICAO has appointed senior and expert technical staff, who will now serve as advisors and observers in the probe, it said.
Few details of the investigation have been released by the Iranian authorities, but Iran's President Hassan Rouhani said in a televised address that it will be overseen by several experts, and that the judiciary will create a special court.
Initially, Iran denied responsibility for the crash, reportedly blaming it on a technical failure but eventually admitted that the operator of a missile defence system had mistaken the plane for a missile and shot it down.
On Tuesday, a spokesperson for the country's judiciary reportedly said at a press conference that the investigation will look into the causes and direct impact of the incident.
A specialised agency of the United Nations, ICAO was created in 1944 to promote the safe and orderly development of international civil aviation throughout the world. It is based in Montreal, Canada.
It sets standards and regulations necessary for aviation safety, security, efficiency, capacity and environmental protection, amongst many other priorities.
The ICAO serves as the forum for cooperation in all fields of civil aviation among its 193 Member States.