Iranian airlines could face severe disruption to their international operations from Wednesday, September 23, as the United States threatens foreign airports and companies with financial penalties for continuing to provide services to the carriers. The warning targets the wider network that helps Iranian airlines operate abroad, including airports, fuel suppliers and ticketing companies.

US Treasury Secretary Scott Bessent said Washington would target businesses that continue supporting Iranian airlines. He said such companies could lose access to the US dollar financial system if they continue providing key services.

“On September 23, all the Iranian airlines will be shut down around the world,” Bessent said on Monday.

Bessent outlined the possible impact on foreign companies in direct terms. He warned that airports and other businesses could face sanctions if they continue serving Iranian carriers.

“If they land, you cannot provide them with fuel, you cannot provide them with landing services, you cannot sell them tickets, or you will be knocked out of the dollar system,” he said.

The US move seeks to extend pressure beyond Iranian airlines themselves. Foreign companies that provide services to sanctioned Iranian carriers could also face secondary sanctions. These measures can restrict their access to the US financial system.

The US Treasury had already expanded sanctions targeting Iran’s aviation sector earlier this month. On September 8, the Treasury’s Office of Foreign Assets Control sanctioned 36 targets linked to Iranian aviation. The action included Iranian airlines that had not previously been designated, along with foreign companies and intermediaries accused of supporting aviation-related activities.

Iranian airlines have faced US restrictions for years. The measures have limited their ability to obtain new aircraft, spare parts and maintenance services. Washington’s latest action forms part of a broader sanctions campaign against Tehran that also covers energy, shipping, technology, gold and digital assets.

The threat of secondary sanctions gives Washington another way to pressure foreign businesses dealing with sanctioned Iranian entities. Companies that continue such dealings can face restrictions on their access to the US financial system.

Bessent also said China is involved in discussions over Washington’s sanctions campaign against Iran. His comments came after talks with Chinese Vice Premier He Lifeng, ahead of a planned meeting between US President Donald Trump and Chinese President Xi Jinping.

China’s economic ties with Iran have made Beijing’s response important to Washington’s efforts to limit Tehran’s access to international finance. Bessent said Chinese officials had been “very engaged” in discussions on the US pressure campaign against Iran.

He also said Washington was holding positive discussions with Chinese financial authorities, including People’s Bank of China Governor Pan Gongsheng, over compliance with US sanctions on Iran.