Iran-US war latest: Iran is ‘completely collapsing’ says Trump as US to announce ‘worst sanctions in history’ against Tehran

Donald Trump ’s administration is set to lay out a programme of sanctions against Iran it has dubbed “economic D-Day”, despite warnings from Tehran that this will be met with an immediate response.

Treasury secretary Scott Bessent wrote in the FT yesterday that: “At dawn begins an economic D-Day – the single greatest financial offensive ever marshalled against an adversary.”

Trump had earlier promised to wage "Economic Warfare and Isolation on an unprecedented scale” on Iran in what he called the “toughest sanctions in history”.

Iran’s security chief Mohsen Rezaei threatened an “earthquake-like” retaliation should the US go ahead with its plan, while also warning Trump’s Gulf neighbours against joining in any sanctions.

Should Trump "take action, our confrontation will be like an earthquake," Rezaei said.

He added: “If the countries surrounding Iran join the Americans in their economic war, not a drop of oil will leave the Persian Gulf and the Strait of Hormuz, and we will also target other oil export routes from the Persian Gulf.”

The US has cancelled a joint amphibious landing exercise with South Korea scheduled for next month, Seoul's Marine Corps announced on Monday.

Washington cited limitations on the availability of American forces resulting from the war in Iran . The US Marine Corps officially informed South Korean officials in June that availability of troops would be restricted for the division-level exercise, known as Ssangyong.

The two allies remained in talks about the eventual resumption of the military drills, a South Korean Marine Corps spokesperson said. He did not elaborate on specific steps being considered to address lost training opportunities or avoid future cancellations.

Oman’s foreign minister Sayyid Badr Albusaidi is to visit Tehran on Tuesday, according to the Iranian foreign ministry.

Spokesperson Esmaeil Baghaei said that the army chief of Pakistan who had assisted in previous mediations would be in the country on Monday.

US treasury secretary Scott Bessent is expected to outline a “D-Day” package of economic sanctions on Iran on Monday after he doubled down on threats in a Financial Times op-ed.

In the piece, he warned that an “economic D-Day is coming for Iran” after similar threats by President Donald Trump last week.

Tehran has called the warnings “economic terrorism” and insisted the move would spell “further defeat” for the US.