US threatens sweeping new sanctions against Iran

The United States is threatening what it calls an unprecedented economic campaign against Iran, warning that countries doing business with Tehran could face severe penalties as Iran vows retaliation against any state that joins Washington’s pressure effort.

US Treasury Secretary Scott Bessent said Washington would apply the “toughest sanctions in history” on Iran and described the campaign as the “greatest coordinated economic isolation in the history of the world.” In an opinion piece for the Financial Times cited by the BBC, Bessent called it “the single greatest financial offensive ever” and said the US-Israel war with Iran was “entering its endgame.”

“The world should understand that our objective is to sever every economic lifeline that sustains the tyrannical regime until Tehran stands alone,” Bessent wrote, according to the BBC.

The latest warnings followed a Truth Social post by President Donald Trump, who said Iran had “failed to take” the opportunity to make a deal and would face “economic warfare and isolation on an unprecedented scale.” He threatened consequences for any country whose “financial institutions, businesses, airports, or government entities” provide what he called a lifeline to Iran.

“Oil smuggling, swap lines, cash transfers, exchange houses, ship registries, front companies – it all needs to stop NOW,” Trump wrote. “This will be an ECONOMIC D-DAY, and we need all of our Allies to stand with the United States of America to isolate, and defeat, the Iran threat.”

Bessent told CNBC the US would pair sanctions with its blockade on Iran. “It is a one-two punch. We have the blockade, and we are going to have the toughest sanctions in history,” he said. “It is going to work in Iran, and we are going to collapse this regime.”

He also warned other governments and companies not to continue trade with Tehran. “We’re going to them and saying: You’re either with us or against us,” Bessent said. “If you insist on doing business with them – either transferring money, buying oil, doing seaborne ship transport – then the US Treasury and the US government, they will put its full might and force towards enforcing against you.”

The Trump administration has already been pursuing an economic pressure campaign against Iran under “Operation Economic Fury” since the war began in February. The US has targeted companies, brokers and tankers accused of helping Iran sell oil abroad, and it has longstanding sanctions on Iran’s oil, shipping and financial sectors.

Iran rejected the new threats. Foreign Ministry spokesman Esmaeil Baghaei said on X that the US announcement amounted to “an assertion of extraterritorial sovereignty” against United Nations member states. He said no country could compel foreign banks, companies or airports to stop commerce with Iran, warning that the result would be “the complete erosion of sovereignty as the foundational basis of the UN-based inter-State system, and a recipe for an abysmal return to full-scale classic colonialism.”

Iranian Foreign Minister Abbas Araghchi said the new measures were “bound to fail.” Posting a screenshot of a 2012 message by former President Barack Obama about earlier sanctions, he wrote: “We have seen this movie before. Same bull. Different bullies.”

Mohsen Rezaei, secretary of Iran’s Supreme National Security Council, told Iranian state broadcaster IRIB that Tehran was urging countries, including its neighbors, not to join the US “economic war.”

“Any country that takes part in imposing economic restrictions on us will be regarded as an enemy,” he said, warning of a “seismic” retaliation. Rezaei said Iran would first try talks, but added: “If they do not act, we will strike. We will target that country’s interests.”

Rezaei also warned that if Gulf neighbors join the US campaign, “not even a drop of oil” would leave the region. One-fifth of global oil and gas exports pass through the Strait of Hormuz in peacetime. Reuters, cited by the BBC, reported that Iran also warned shipping not to pass through the strait without its permission.

China pushed back against Washington’s approach. “Imposing sanctions and pressuring do not help to solve the issue,” Foreign Ministry spokesman Lin Jian said, calling for diplomatic and political efforts.

The United Arab Emirates last week announced an indefinite trade embargo on Iran after accusing Iranian forces of firing two ballistic missiles at the country, an allegation Tehran denies.