China said on Tuesday it opposed “illegal” US sanctions on Iranian airlines, a day after Treasury Secretary Scott Bessent threatened potential measures in a televised interview.

An Iran Air Airbus A330-200. Photo: Wikicommons.

Bessent told CNBC that “all the Iranian airlines will be shut down around the world” in a matter of days under the weight of American sanctions, as the Trump administration seeks to ramp up pressure on Tehran.

Beijing — a top economic partner and diplomatic backer of Iran — slammed the threats on Tuesday, calling such measures “illegal”.

‘Illegal unilateral sanctions’

“China consistently opposes illegal unilateral sanctions that lack a basis in international law or authorisation from the UN Security Council,” foreign ministry spokesman Guo Jiakun told a news conference.

The criticism comes just before US President Donald Trump’s summit starting Thursday with Chinese leader Xi Jinping.

US President Donald Trump and Chinese President Xi Jinping at Zhongnanhai in Beijing on May 15, 2026. Photo: The White House, via Flickr.

The United States and Iran have been at war since late February, when US-Israeli strikes killed the Islamic republic’s supreme leader and senior military officials at the start of a broad offensive.

Tehran countered by blocking the Strait of Hormuz, a vital waterway for energy transit, causing global oil prices to surge as the conflict spread in the Middle East.

‘Economic D-Day’

The United States imposed sanctions this month on “all remaining Iranian airlines” that had yet to face such penalties.

The Treasury Department also took aim at targets for supporting Iran’s aviation sector, including firms based outside Iran.

US Secretary of the Treasury Scott Bessent at the World Economic Forum in Davos-Klosters, Switzerland, on January 20, 2026. Photo: World Economic Forum, via Flickr.

“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,” Bessent said in the interview.

He had previously vowed the United States would declare “economic D-Day” on Iran and pledged to choke off Tehran financially.

Bessent’s comments came a day after he met with Chinese Vice Premier He Lifeng for economic talks, laying the groundwork for the meeting between the two countries’ leaders this week.