The order, issued on Friday, does not specify the tariff rate that could be imposed but cites 25 percent as an example. It states that the tariff could apply to goods imported into the US from any country that “directly or indirectly purchases, imports, or otherwise acquires any goods or services from Iran”.

Trump has not commented directly on the order but reiterated that Iran must have “no nuclear weapons” while speaking aboard Air Force One on Friday night.

The move comes as talks continue between senior US and Iranian officials in Oman, following several weeks of threats from both sides. Earlier this year, Trump warned of a 25% tariff on countries doing business with Iran in a post on Truth Social. On 12 January, he wrote: “Effective immediately, any country doing business with the Islamic Republic of Iran will pay a tariff of 25 percent on any and all business being done with the United States of America.” At the time, no further details were provided on how the tariffs would be implemented.

The White House said the latest executive order reaffirmed the “ongoing national emergency with respect to Iran” and noted that the president may modify it if circumstances change. The statement said: “The President is holding Iran accountable for its pursuit of nuclear capabilities, support for terrorism, ballistic missile development, and regional destabilisation that endanger American security, allies, and interests.”

Separately, the US State Department announced on Friday that it was sanctioning 15 entities “that have traded in Iranian-origin crude oil, petroleum products, or petrochemical products”.

There was no immediate response from Iran to either announcement. The country is already subject to extensive sanctions imposed by the US and other Western powers over its nuclear programme. (BBC)