Rouhani said, "Anyone who calls the Iranian people terrorists does not have the right to sympathize with the people".
USA officials said Iran appeared to be using local police, the Basij militia and Islamic Revolutionary Guard Corps to crack down on protests, much as it did in 2009 to crush the last major bout of unrest.
Iranian President Hassan Rouhani has hit back at Trump's comments, saying the United States leader - whose "whole being is against the nation of Iran - has "no right" to sympathise with protesters". The protest movement's leaders remain under house arrest years later.
The rallies, scheduled weeks earlier, commemorated a mass 2009 pro-government rally challenging those who rejected the re-election of hard-line president Mahmoud Ahmadinejad amid fraud allegations. The president came close to making such a promise in a tweet on New Year's Day that began with "Iran is failing at every level despite the awful deal made with them by the Obama Administration" and ended with the exclamation "TIME FOR CHANGE!"
The rallies come after Iran's Supreme Leader Ayatollah Ali Khamenei on Tuesday blamed days of protests across the country on meddling by "enemies of Iran".
Trump's administration also demanded a snap U.N. Security Council meeting to debate unrest that has killed 21 people - mostly protesters. Foreign leaders such as US President Donald Trump and Israeli Prime Minister Benjamin Netanyahu have praised the protests, but there is no evidence of direct interference.
To the editor: Trump tweeted that Iranians "are finally getting wise as to how their money and wealth is being stolen and squandered". Foreign powers long vied for control over Iran's natural resources.
Iran's unemployment rate reached a three-year high of 12.7% in the second quarter of 2016, according to the World Bank.
The protests began last week over economic concerns, reports say, but have shifted toward anti-government demonstrations focused on Iran's clerical rulers.
"Instead of wasting his time sending useless and insulting tweets regarding other countries, he would be better off seeing to the domestic issues of his own country such as daily killings of dozens of people... and the existence of millions of homeless and hungry people", Qassemi stated. Experts estimate a smaller, but potentially more widespread turnout than in 2009. "With the demonstrations lacking clear leadership or a coherently articulated positive programme, the tide ultimately will turn back in the regime's favour, helped by a range of concessions and targeted crackdowns", Ghoncheh Tazmini, an associate member of the Centre for Iranian Studies at the School of Oriental and African Studies, told TWW.Dr. Vaez also saw an opportunity for President Rouhani, who could "leverage public discontent to push the political establishment toward structural changes so fervently desired by the population".
Trump's United Nations envoy, Ambassador Nikki Haley, has called for an emergency Security Council meeting on Iran, saying the United Nations needed to speak out in support of the protesters. "What we would like to see above all is the regime change its behavior, in a whole lot of ways, but in particular towards the protesters", Peek said.
Washington must continue to drive up the long-term political, economic, and military costs of Iran's military interventions in Syria, Iraq, and Yemen. Nevertheless, even if imminent change might be unlikely, "the idea of popular democratic opposition has been rehabilitated", Dr. Tazmini adds."The protests have offered a salutary warning that the system needs to adapt to societal change and popular aspirations".