The looming escalation comes as both sides missed a 60-day ceasefire window to reach a deal, closing off the formal truce mechanism aimed at ending the Middle East war now in its sixth month.

In a post on X on Sunday evening stateside, Bessent said "at dawn begins an economic D-Day," framing the coming measures as the "endgame" for Washington's campaign against Tehran.

The new measures will add to an extensive sanctions regime already targeting Iran's banking, energy, aviation and cryptocurrency sectors. The Trump administration has claimed that Iran's economy is in freefall, with runaway inflation and a collapsing currency.