U.S. Treasury Secretary Scott Bessent has warned Iran of an economic D-Day, as it prepared to roll out economic sanctions that target Iran’s trade partners. The remarks followed shortly after Iran’s President Masoud Pezeshkian defended a memorandum of understanding with the United States as the best way out of a stalled war. Iran in turn vowed to shut down all oil exports from the Gulf “if the economic war continues”.
In a post on X, Mr. Bessent wrote, “President Trump has dismantled Iran’s military capabilities, destroyed nearly 100% of its military factories, and buried its nuclear programme. We are now entering the endgame. At dawn begins an economic D-Day — the single greatest financial offensive ever marshaled against an adversary.”
“The Islamic Republic has subsisted by dressing extortion as security guarantees. It has drawn strength from a calculus that regards Iranian retaliation as certain and American enforcement as negotiable. Under President Trump, that era is over. And those who fear the danger of defying Tehran ought not to discount the cost of testing Washington,” he said.
He further added, “The President has created the conditions to leverage every agency, every authority and action many assumed we would never summon. Our objective is to sever every economic lifeline that sustains the tyrannical regime until Tehran stands alone.”
The U.S. Treasury Secretary will hold a press conference at 1 p.m. EDT (1700 GMT) on Monday (August 24, 2026) amid promises to reveal even more severe measures on a country that has endured near-continuous economic sanctions since the Islamic Revolution of 1979.
The statement arrives closely on the heels of U.S. President Donald Trump’s call to impose economic sanctions against Iran. The remarks underscore the Trump administration’s shifting stance of an economic rather than military pressure on Tehran as the war drags toward the six-month mark.

Mr. Trump has warned of economic consequences against any country that provides “any type of lifeline to Iran”, and Mr. Bessent has urged cooperation with Washington by China, which buys more than 80% of Iran’s shipped oil, according to 2025 data from analytics firm Kpler.
The warring nations have not conducted military strikes against each other for weeks, but they also have not engaged in meaningful talks to end the six-month-old conflict.
‘U.S. sanctions will fail’
But, Iran has dismissed the threat of new U.S. sanctions as a sign of desperation and said the expected new measures would fail to defeat Tehran. Mohsen Rezaei, secretary of Iran’s Supreme National Security Council, suggested economic retaliation.
“If the economic war continues, not a single drop of oil will be exported, neither through the Strait of Hormuz nor from anywhere in the Persian Gulf,” Mr. Rezaei wrote in a social media post. “Iran will regard any country’s participation in or support for America’s economic war against the Iranian people as an act of war.”
In a defying stance, Iran’s Foreign Minister Abbas Araghchi also termed the measures as “repetitive scenarios”. “The fact that they [U.S. leaders] have moved on from military operations… to bring up the same old plans shows that they are desperate,” he noted.

He urged Washington to speak to Iran respectfully to find “a solution based on justice and honor.” Furthermore, he added, “We have never been afraid. All of their actions—whether blockades or other military moves they have made—have failed, and this new issue of theirs will fail as well.”
Support for U.S. sanctions an ‘act of war’, says Iran
Iran’s Supreme National Security Council, Mohsen Rezaei, on Sunday (August 23, 2026) warned Tehran will see any country’s support for new U.S. economic measures against the Islamic Republic as an “act of war”, while Iran’s President defended the MoU with the U.S.
“If (Trump) wants to do something, we will retaliate in a seismic manner,” he had told the state broadcaster in an interview that aired late on Saturday (August 22, 2026). He said Iran would target other oil-shipping routes from the Persian Gulf — alternatives to the Strait of Hormuz.
His remarks came even though Iran’s President Masoud Pezeshkian said the memorandum of understanding signed in mid-June was the best way to move beyond a situation of “neither war nor peace”, adding that Tehran can’t attract investment nearly six months after the war began.
“There is not a single provision in this agreement that amounts to capitulation,” Mr. Pezeshkian said in a speech published by state-run IRNA. “The supreme leader sets the policies, and we will follow that path.”
The interim deal opened a 60-day period for talks aimed at ending the war and reaching an accord on Iran’s nuclear programme. That period ended last week with no signs of compromise or extension.
(With inputs from agencies)
Published – August 24, 2026 02:57 pm IST