US operators have been prohibited from operating in Iranian and Iraqi airspace in relation to the geopolitical tensions and the potential risk to civil air traffic.

The US FAA’s restriction also covers the Persian Gulf and the Gulf of Oman.

It states that the heightened military activities and increased political tensions in the region pose an “inadvertent risk” to US civil aviation.

The risk arises from the potential for “miscalculation or misidentification”.

Iranian Civil Aviation Organisation deputy director Morteza Dehghan had stated, on 7 January, that the country’s airspace was safe and that no international restrictions had been imposed on flights from Iran.

Iranian investigators have started a probe into the loss of a Ukraine International Airlines Boeing 737-800 which came down shortly after departure from Tehran’s Imam Khomeini airport on 8 January.

While there is no immediate evidence that the crash resulted from hostile action, military activity overnight – including the firing of missiles at Iraqi bases – has inevitably introduced additional complexity to the investigation.

Transport minster Mohammed Eslami has vowed an “urgent” investigation into the cause of the crash involving flight PS752 to Kiev.

It had been transporting mainly Iranian and Canadian passengers, according to Ukraine’s minister of foreign affairs, Vadym Prystaiko, as well as citizens from Ukraine, Sweden, Germany, the UK and Afghanistan.