THE United States doubled down over its vow to “squash” Iran’s economy to help bring about regime change in Tehran.

US Treasury Secretary Scott Bessent demanded support from allies to support Washington’s efforts.

He told CNBC that “we are going to collapse this regime. It is time for our allies and the rest of the world to make a decision.

“You are either with us or against us,” he said.

Mr Bessent’s remarks on Thursday come after US President Donald Trump warned countries providing “any type of lifeline” to Iran that they will face “tremendous economic consequences.”

Mr Bessent did not explain what measures were being considered, but said they would minimise the need for a “large-scale kinetic restart” of the conflict.

The US and Israel launched an illegal and unprovoked attack against Iran on February 28, arguing the strikes were to prevent the Iranians from developing nuclear weapons, which Tehran has always denied planning to do.

Iran retaliated by attacking Israeli and US bases and assets across the Middle East.

Since then, Iran has closed the Strait of Hormuz – the waterway through which some 20 per cent of the world’s oil and liquefied natural gas used to transit – causing wild fluctuations in prices on world markets.

The US and Iran agreed a ceasefire in April and then another in June which included a Memorandum of Understanding that set out a roadmap for ending the conflict.

But the US broke the truce and talks have since stalled.

Instead of returning to war, President Trump switched approach and vowed to unleash the “most crushing economic operation ever taken against any country.”

Mr Bessent said the new economic penalties will be part of “the greatest co-ordinated economic isolation in the history of the world,” and confirmed that further details will be made public at a press conference on Monday.