US Treasury Secretary Scott Bessent said the sanctions against Iran will “tighten the noose and block every potential source of revenue”.

Yet, many experts disagree. Advisory firm Oxford Economics said the direct impact on Iran’s revenues would be “somewhat of a damp squib”.

Ali Vaez, deputy director at the International Crisis Group, said: “Anything that moves in Iran has already been sanctioned by multiple layers of sanctions, in fact.

“So the question now is one of enforcement. Does the United States have what it takes to impose fines and levies on countries that continue to trade with Iran?”

He noted how the US started an economic war with China, Iran’s biggest trading partner, last year but “backed out of it”.

Former senior advisor at the state department Aya Ibrahim said the US’s overreliance on them “incentivises countries to find ways around that system”.

She also raised concerns that the sanctions may have the biggest affect on people, rather than economies, as they “deny people necessities to stay alive”.

Meanwhile, global markets have had a muted response to the announcement.

Global oil prices fell following the announcement, but are still far higher than pre-war levels.

Stock traders were even less moved by the news, with the major indexes of the biggest companies listed in the US, Europe, and Asia barely shifting.

The US will has a way to go before it convinces economists, investors, and the nations trading with Iran that its sanctions threat is to be taken seriously.

Additional reporting by Miguel Roca-Terry