The head of the US Treasury, Steven Mnuchin, has said that his department will be reviewing licenses granted to Airbus and Boeing to sell aircraft to Iran, reports Reuters. Mnuchin made the announcement to the House Ways and Means Committee, alongside calls for greater sanctions to be applied to Iran, North Korea and Syria.

Since the lifting of sanctions against Iran in 2015, the country's airlines have busily been attempting to renew their ageing fleets. Iran Aseman Airlines has signed a Memorandum of Understanding (MOU) with Boeing for the purchase of thirty B737 MAX aircraft, with options for thirty more. IranAir has a firm order for fifty B737-8s, fifteen B777-300(ER)s, and fifteen B777-9s, as well 100 Airbus aircraft. It recently concluded a deal to acquire up to forty ATR72-600s from ATR - Avions de Transport Régional.

"Boeing continues to follow the lead of the U.S. government with regards to working with Iran's airlines, and any and all contracts with Iran’s airlines are contingent upon U.S. government approval," a Boeing spokesperson is reported as saying.

The aircraft manufacturers require Washington's approval to sell to Iran because a large proportion of their aircraft components are made in the United States.