Iran vows 'devastating' response as US threatens toughest ever economic hit

By Jana Choukeir and Susan Heavey DUBAI/WASHINGTON, Aug 21 (Reuters) - Iran said on Friday that its response to any new U.S. threats would be "devastating" after Washington pledged to impose the toughest financial penalties in history with the aim of toppling the Iranian leadership. U.S. Treasury chief Scott Bessent's comments on Thursday followed a warning from President Donald Trump of economic consequences against any country that provided "any type of lifeline to Iran." Bessent promised…