BEIJING — The United States has threatened the “economic asphyxiation” of Iran, but analysts say that a successful chokehold would require unlikely cooperation from China.

Almost six months into the Middle East war, Washington this week laid out plans to expand sanctions against the Islamic republic, warning that any nation which continued to enable Tehran would become a “global pariah”.

China is among countries whose entities have already been hit by the sweeping US plan, with Treasury Secretary Scott Bessent telling Beijing to “get with the programme”.

But Beijing instead has defended its cooperation with Tehran and vowed to safeguard its interests.

The apparent impasse is likely to further strain ties between Beijing and Washington, ahead of an expected visit by China’s President Xi Jinping to the US capital in September.

Iran has weathered sanctions for decades, using complex international financial networks to evade restrictions.

Cutting off Iran “would certainly require China’s help”, said political scientist Dylan Loh of Singapore’s Nanyang Technological University.

Beijing is a key customer for Iranian oil, while “a good amount of their trade also relies on (the Chinese currency) renminbi, which can be outside the reach of US sanctions”, Loh told AFP.

Before the war, Tehran exported millions of barrels of oil a day, mostly to China.

“Oil is the central economic lever,” said Nino Lezhava, a fellow at the Washington-based Centre for European Policy Analysis.

Although most ship traffic in the vital Strait of Hormuz is still blocked, China is not totally cut off from Iran’s crude thanks to the highways and railways of Central Asia, said Sun Degang, a professor of political science at Shanghai’s Fudan University.

Despite Chinese purchases being lower than before, they remain an important source of revenue.

“Simply continuing to... maintain commercial channels and provide alternative payment mechanisms can substantially reduce the effectiveness of economic isolation,” said Lezhava.