US Treasury Secretary Scott Bessent says all Iranian airlines will be shut down on September 23 by the threat of secondary sanctions on air services providers, and that Chinese officials have been “very engaged” in the US economic pressure campaign against Iran, Reuters reports.

Bessent tells CNBC, after he concluded talks on Sunday night with Chinese Vice Premier He Lifeng, that when Iranian airlines land at an airport, “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 adds that the US is having positive discussions with Chinese financial authorities, including People’s Bank of China Governor Pan Gongsheng, on compliance with US sanctions on Iran.