WASHINGTON:The United States on Monday expanded its threat of secondary sanctions against countries

US Treasury Secretary Scott Bessent described the campaign as an "economic D-Day", saying Washington was launching an "economic onslaught" aimed at cutting the financial lifelines of Iran and forcing countries that continue doing business with Tehran to risk losing access to the dollar-based financial system.

"We are launching an economic onslaught against Iran's financial connections around the globe," Bessent said, adding that the US objective was to sever every economic lifeline sustaining the Iranian regime until Tehran stood alone.

The Treasury Department said it had issued determinations against five sectors - digital assets, technology, gold, aviation and shipping - that Iran was using to support its economy.

It also imposed sanctions on nearly 60 entities, individuals and vessels as part of the expanded campaign. The department said it had mapped networks, facilitators and financial channels used by Iran to smuggle oil and evade sanctions, and would work with US partners to target sources of what it described as Iran's "illicit revenue".

Almost six months into the war, the two sides remain locked in a stalemate, with peace efforts stalled and the Strait of Hormuz still closed.

US President Donald Trump had claimed that Iran was "completely collapsing". Trump has increasingly shifted towards economic pressure as the conflict's costs have mounted, while maintaining that the measures are necessary to ensure Iran does not obtain a nuclear weapon.

The conflict has pushed energy prices higher worldwide and added to domestic political pressure on his administration. The United States has maintained sanctions against Iran for decades, targeting its oil revenues, aviation sector, cryptocurrency activities, weapons procurement and enterprises controlled by the Islamic Revolutionary Guard Corps (IRGC).