Iran's judiciary should take tough measures against protesters and anyone who thinks the country's rulers will fall is dreaming, a senior cleric said.
The Islamic Republic has been gripped by demonstrations that erupted after the death in police custody of 22-year-old Mahsa Amini last month.
"The judiciary should deal with the rioters - who betrayed the nation and poured water into the enemy's watermill - in such a way that others don't again fancy to riot," hardline cleric Ahmad Khatami said in a Friday prayers sermon in Tehran, Iranian media reported.
"They have told deceived kids that if they stay in the streets for a week the regime will fall. Dream on! The judiciary should deal with rioters in such a way they would never aspire to riot."
Iran has blamed "thugs" linked to "foreign enemies" for the unrest.
Protesters are calling for the downfall of the Islamic Republic
The nationwide protests have turned into one of the boldest challenges to Iran's clerical rulers since the 1979 revolution. Protesters have called for the downfall of the Islamic Republic, although the protests do not seem close to toppling the system.
As protests continued in several cities, the activist website 1500tasvir posted a video it said showed a demonstration in the central city of Isfahan and footage purporting to show protesters lighting fires on streets of the northwestern city of Mahabad late on Thursday.
Videos of protests have been delayed because of internet restrictions imposed in Iran by authorities, activists say.
The activist news agency HRANA said in a posting that 244 protesters had been killed in the unrest, including 32 minors.
It said 28 members of the security forces were killed and over 12,500 people had been arrested until Thursday in protests in 114 cities and towns and some 81 universities.