The U.S. Treasury chief told Congress on May 24 that he is looking for ways to increase sanctions on Iran, including by reviewing licenses the Treasury previously granted to Boeing and Airbus to sell aircraft to Iran.
"We will use everything within our power to put additional sanctions on Iran, Syria, and North Korea to protect American lives," Treasury Secretary Steve Mnuchin said in testimony to the House Ways and Means Committee.
"I can assure you that's a big focus of mine and I discuss it with the president," he said, adding that the Trump administration is convinced that sanctions "really work."
Mnuchin did not elaborate on the department's review of the aircraft sale licenses, which were issued by the Treasury last year under a 2015 agreement between Tehran and world powers to lift economic sanctions in return for curbs on Iran's nuclear activities.
His statements followed President Donald Trump’s call on Iran to stop funding "terrorists and militias" during a trip this week to the Middle East.
The Boeing aircraft sale was the biggest deal for a U.S. business contemplated in the landmark nuclear accord, while the Airbus sales were also among the largest business deals to come out of the agreement.
IranAir has agreed to buy 200 U.S. and European passenger aircraft worth up to $37 billion at list prices, though such deals typically include big discounts.
They include 80 jets from Boeing and 100 from Airbus. All the aircraft need U.S. licenses because of their reliance on U.S. parts.
Most of Iran's aging fleet of 250 commercial planes were purchased before 1979, and only 162 were operational last year, with the rest grounded because of a lack of spare parts.
Iran has said that halting the aircraft sales would breach the nuclear agreement, though some legal experts say the Treasury has the authority to withdraw the licenses.
For Boeing, losing the IranAir deal could force it to cut back production of its 777 passenger jetliners.
"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 spokeswoman told Reuters by e-mail.