Tehran's main prosecutor said that those protesters involved in burning government buildings, clashing with armed forces, and "committing sabotage" would face the death sentence, Reuters reported, citing Iranian state media on Friday.
The decision came as the protests in Iran approached their 14th consecutive day, with riots and violent clashes reported in several cities, while a total shutdown of the internet was imposed by the regime nationwide.
Earlier on Friday, reports from the Iranian Supreme National Security Council (SNSC) assured that it had warned the judicial system that security forces will show "no leniency towards saboteurs."
The SNSC said that security and law-enforcement forces had been deployed to "neutralise the destabilisation plans of the Zionist regime [Israel] and its godfather, the United States".
The statement assured that foreign actors were influencing the protests, and strongly condemned attacks on religious symbols and symbols of the Islamic Republic, like the burning of flags and statues of the late IRGC Quds Force Commander Qasem Soleimani.
Khamenei accuses Trump of killing 'thousands of Iranians'
The Islamic Republic's supreme leader, Ayatollah Ali Khamenei, accused protesters of acting on behalf of US President Donald Trump, warning that Tehran would not tolerate people acting as "mercenaries for foreigners."
"Last night in Tehran & some other cities, a bunch of people bent on destruction came and destroyed buildings that belong to their own country in order to please the President of the US and make him happy," he said.
He also made a post on social media where he criticized Trump, accusing him of killing "thousands of Iranians during the 12-Day War" and now "saying that he is on the side of the Iranian nation."
"The US President has said that if the Iranian government does such-and-such, I’ll take the side of the rioters. The rioters have put their hopes in him. If he’s so capable, he should manage his own country," he added.
Finally, he compared Trump to "the Pharaoh Nimrod, Mohammad Reza Pahlavi," and said that "such rulers saw their downfall when they were at the peak of their hubris. He too will fall."
Alex Winston contributed to this report.