India, Aug. 23 -- Washington and Tehran traded fresh threats this week as US President Donald Trump vowed to unleash what he called the "most crushing economic operation ever taken against any country" against Iran, prompting Tehran to warn its response would be "devastating," a standoff that has now drawn a direct warning from a top US senator about the risk to global energy markets.

Trump made the threat in a post on Truth Social, declaring that Iran would face "economic warfare and isolation on an unprecedented scale" after nearly six months of war and stalled negotiations to reopen the Strait of Hormuz.

US Treasury Secretary Scott Bessent followed on, telling CNBC that Washington was preparing the "toughest sanctions in history" alo...