U.S. Treasury plans toughest sanctions in history on Iran

U.S. Treasury Secretary Scott Bessent said the United States will impose the toughest sanctions in history on Iran, describing the move as a one-two punch with the existing naval blockade.

Bessent made the comments on Thursday, a day after President Donald Trump warned of economic warfare and isolation on an unprecedented scale. Trump said any country providing a lifeline to Iran through financial institutions, businesses, airports or government entities would face tremendous economic consequences.

Bessent told CNBC that more details would come on Monday. He framed the sanctions as a way to lessen the need for large-scale kinetic operations. "We are going to collapse this regime. It is time for our allies and the rest of the world to make a decision," he said. "You are either with us or against us."

The planned measures form part of what Bessent called the greatest coordinated economic isolation in the history of the world. He said the U.S. would enforce penalties against partners that continue transferring money, buying Iranian oil or otherwise supporting Tehran.

Iran has already faced decades of U.S. sanctions. The current campaign follows the April naval blockade, which was paused for a month in mid-June, and earlier strikes on Iranian nuclear sites. Tehran has developed smuggling routes and new markets, particularly for oil, to absorb the pressure.

Iranian Foreign Minister Abbas Araghchi dismissed the threats, saying they would only increase hostility. China has also indicated that sanctions do not help.

Bessent's announcement comes as the Trump administration faces domestic pressure from high fuel prices and the approaching midterm elections. The economic campaign is presented as an alternative to restarting large-scale military action after months of conflict that have depleted key weapons stocks.

The full package is expected to target remaining revenue streams, including oil smuggling, swap lines, cash transfers, exchange houses, ship registries and front companies.