A top US official has made clear that the US government is unlikely to issue any licenses that would allow companies like Airbus and ATR to continue supporting aircraft in service with Iranian airlines.

The official likewise says the US government is unlikely to approve a new request by ATR to sell more turboprops to Iranian carriers.

Those companies recently delivered aircraft to IranAir, but their ability to support the aircraft remains uncertain due to the US government's recent harder stance toward Iran.

Under direction of President Donald Trump, the US is ending participation in the Iran nuclear deal and revoking licenses made possible by the deal that enabled aircraft manufacturers to sell aircraft and aircraft components that contain US-made parts to Iranian airlines.

Aircraft manufacturers have to "obtain licenses from us" to fully support aircraft delivered to Iranian airlines, US Department of Treasury assistant secretary of terrorist financing Marshall Billingslea told FlightGlobal on 9 July.

"At this stage, I think we are not in a position to suggest we would be issuing such licenses," he says.

Billingslea also suggests the US is unlikely to approve a more-recent application by ATR for authority to sell more turboprops to Iranian airlines.

"We are not in a position to show flexibility on transactions with Iran at this time," he says.

Neither Airbus nor ATR immediately responded to requests for comment.