“Iranian Patriots, KEEP PROTESTING – TAKE OVER YOUR INSTITUTIONS!!!” Trump wrote on his Truth Social platform.

“Save the names of the killers and abusers. They will pay a big price.

“I have cancelled all meetings with Iranian Officials until the senseless killing of protesters STOPS. HELP IS ON ITS WAY,” he added

Trump did not specify what form the promised “help” would take, in a message that backed regime change in the Islamic Republic – marking a change in the US stance from one day ago.

Yesterday, his press secretary Karoline Leavitt told reporters that a channel for diplomacy with Tehran remained open, saying that Iran was taking a “far different tone” in private discussions with Trump’s special envoy Steve Witkoff.

Trump on Monday also announced a 25% tariff on any country doing business with Iran, ramping up pressure as a rights group estimated the crackdown has killed at least 648 people.

Iranian authorities insist they have regained control after successive nights of mass protests that have posed one of the biggest challenges to the clerical leadership since the 1979 Islamic revolution ousted the shah.

However, rights groups accuse the government of using live fire against protesters and masking the scale of the crackdown with an internet blackout that has now lasted more than four days.