Students have a right to protest but must "understand the red lines", Iran's government spokeswoman said, in the first official reaction to renewed anti-government rallies on campuses.
University students kicked off a new semester with gatherings over the weekend in which they revived slogans from nationwide protests against the country's clerical leadership that peaked in January and were met by a deadly crackdown.
On Monday, the third consecutive day of the campus protests, videos geolocated by AFP showed students at a university in Tehran burning the Iranian flag adopted after the 1979 revolution that toppled the monarchy.
"Sacred things and the flag are two examples of these red lines that we must protect and not cross or deviate from, even at the height of anger," government spokeswoman Fatemeh Mohajerani said on Tuesday.
She added that Iran's students "have wounds in their hearts and have seen scenes that may upset and anger them; this anger is understandable".
The initial wave of protests began in December, sparked by economic woes in the sanctions-hit country, but soon grew into nationwide demonstrations that crested on January 8 and 9, posing one of the largest challenges to Iran's leaders in years.
The unrest prompted a government crackdown that led to the deaths of thousands of people.
A US-based rights group has recorded more than 7,000 deaths, while warning that the full toll is likely far higher.
Iranian officials acknowledge more than 3,000 deaths, but say the violence was caused by "terrorist acts" fuelled by the United States and Israel.
Mohajerani said a fact-finding mission is investigating "the causes and factors" of the protests and will provide reports.
US pressure
The crackdown in January prompted US President Donald Trump to threaten to intervene militarily on the protesters' behalf, though the focus of his threats soon shifted to Iran's contentious nuclear programme.
Since then, the US has carried out a massive military build-up in the Middle East aimed at pressuring Tehran into cutting a deal, even as the two sides pursue indirect negotiations, set to resume on Thursday in Geneva.
Iran insists its nuclear programme is for civilian use, but the West believes it is aimed at building an atomic bomb.
Iran has vowed to retaliate "ferociously" against any attack from the United States, even a limited one, which Trump has publicly acknowledged he is considering.
Trump on Monday denied US media reports that the country's top military officer, General Dan Caine, had flagged the risks of a major operation against Iran—pointing to munitions shortages and the potential for lengthy entanglement, among others.
"General Caine, like all of us, would like not to see War but, if a decision is made on going against Iran at a Military level, it is his opinion that it will be something easily won," Trump wrote on his Truth Social network.
