Iran warns of 'faster, heavier, more painful response' to US attacks
The comments came a day after Washington said it had struck Iranian oil tankers in response to Tehran's attacks on US warships in the region.
Iran's top negotiator has warned of "a faster, heavier, and more painful response" to US attacks, as hostilities between the two sides escalate.
Parliament speaker Mohammad Bagher Ghalibaf said on Sunday that Americans must understand "before it is too late" that the "rules of the game have changed", according to a translation of his comments on state media.
His comments come nearly a week into renewed fighting between Iran and the US, and a day after Washington said it struck Iranian oil tankers in response to Tehran attacking American warships in the region's waters.
US President Donald Trump said this week that the renewed fighting would not last "too long", echoing comments both he and his administration have frequently made since the now six-month-long war began in February.