Previous resolutions have targeted a handful of senior figures in the Iranian nuclear programme. But in the latest proposal, Washington has presented governments with a list of dozens of companies suspected of being fronts for the Revolutionary Guard, which has taken over a sizeable chunk of the Iranian economy, including the capital’s airport and metro railway system, in recent years.

Particular effort is being paid to Dubai, which has strong trade links with Tehran, but has not yet followed the lead of neighbouring Abu Dhabi in cracking down on suspicious company registrations, front companies for Iran entities in free trade zones and intercepting illicit cargo.

Though Arab states are nervous about upsetting a volatile neighbour and are unlikely to go public about their cooperation with the US, Washington is confident they will collaborate in private. Four Gulf countries have already agreed to have US anti-missile batteries placed on their territory.

The help of the Gulf states will be needed as the Obama administration fully expects China and Russia, both veto-holding members of the UN Security Council, to follow their previous practice and weaken and delay the sanctions package, which is already slipping beyond the first deadline of late March.

However, Western officials are convinced UN sanctions have played their part in constraining Tehran, not least by acting as a powerful political tool, while additional measures have succeeded in choking its access to suppliers and financing.

Matthew Levitt, a former deputy assistant secretary for intelligence at the Treasury Department, said “sanctions can be extremely effective as a means of disrupting the progress” of the ballistic missile and nuclear programme, “even if they are not bringing it to a halt”.

Though Iran has been adept at finding new markets and new friends, the US treasury has barred numerous Iranian banks from transferring money to and from the US, and more than 80 foreign banks have or will cut ties with Iran.