U.S. Treasury Secretary Scott Bessent speaks to reporters at the White House on August 20, 2026 in Washington, DC, USA.
Kevin Lamarque | Reuters
Treasury Secretary Scott Bessent said Monday that the United States would launch the “largest financial attack in history” against Iran, while Iran threatened to seize ships that violated rules for passage through the Strait of Hormuz.
The impending escalation comes as the formal ceasefire mechanism aimed at ending the Middle East war expires in its sixth month, with both sides missing a 60-day ceasefire deadline to reach an agreement.
“At dawn, economic D-Day will begin,” Bessent said in a post for the X newspaper on Sunday evening, US time, and identified future measures as the “ultimate goal” of the U.S. government’s campaign against Tehran.
The new measures will add to a broader sanctions regime already targeting Iran’s banking, energy, aviation and cryptocurrency sectors. The Trump administration claimed that Iran’s economy was in free fall due to runaway inflation and currency collapse.
Bessent also warned that “states that serve as financial arteries for declining regimes should expect to share in that isolation,” a word aimed at foreign governments that still continue to do business with Tehran. He previously warned of further secondary sanctions against countries and entities doing business with Iran.
In response, Iran warned Gulf states not to participate in the U.S. economic package and tightened its grip on the choke point through which roughly one-fifth of the world’s offshore oil flow passed before the war.
On Saturday, Mohsen Rezaei, a longtime military commander who was sworn in as the new secretary of Iran’s Supreme National Security Council earlier this month, vowed to target oil-rich neighbors if they join US efforts to further isolate Iran.
“Any country that becomes a partner that imposes economic restrictions on us will be considered by us as an enemy,” he said in an interview with Iranian state television.
In a series of posts on X on Sunday, Iran’s state-run Persian Gulf Straits Authority (PGSA) warned that vessels violating Hormuz port navigation rules could face penalties including “fines, seizures and confiscation” during future passage.
Iranian Foreign Minister Abbas Araghchi also dismissed the threat of new U.S. sanctions as a “desperate” ploy, insisting that U.S. actions such as the blockade were doomed to failure.
According to local media reports, Tehran’s parliament on Sunday approved an article stipulating that Tehran pays for services provided by ships passing through the difficult waters of Hormuz. The bill still requires full parliamentary approval.
Oil prices retreated in Asian trading on Monday despite an impending escalation. U.S. benchmark West Texas Intermediate futures fell about 1.3% to $85.93 per barrel, while international benchmark Brent crude oil fell 1.3% to $93.22 per barrel.
Britain’s Maritime Trade Service reported no confirmed attacks in the Channel in the 48 hours to Sunday, but warned that mine danger zones remained active and there was a “continued risk of drifting or uncharted mines”.
