The demonstrations have been over the falling living standards in the country and have spread to the capital of Tehran.
A revolutionary guard’s general has said those protesting Iran’s regime will be met with an “iron fist”.
State media also quoted Interior Minister Abdolreza Rahmani Fazli as saying: “Those who damage public property, violate law and order and create unrest are responsible for their actions and should pay the price.”
In the provincial city of Dorud, two protesters were reportedly killed on Saturday night.
There were even calls for the removal or death of Iran’s Supreme leader, Ayatollah Ali Khamenei, in the cities of Khoramabad, Zanjan and Ahvaz.
Iran’s interior minister Abdolreza Rahmani-Fazli said: “Those who damage public property, disrupt order and break the law must be responsible for their behaviour and pay the price.
“The spreading of violence, fear and terror will definitely be confronted.”
President Donald Trump tweeted: “Oppressive regimes cannot endure forever, and the day will come when the Iranian people will face a choice. The world is watching!”
In Tehran, 70 students went to the university to hurl rocks at the police, while they chanted : “Death to the dictator”.
The protesters are angry at President Hassan Rouhani who was re-elected on a promise to improve the country’s economy.
The demonstrations have called for an end to ongoing Iran involvement in regional conflicts in Iraq and Syria.
Riot police have been using clubs to disperse protesters.
Protesters have attacked banks and government buildings and burned a police motorcycle.
Ahmad Khatami, a hardline cleric who leads Friday prayers in the capital Tehran, called for capital punishment for those chanting slogans against the values of the Islamic Republic.
Unemployment rose to 12.4 percent this fiscal year up 1.4 percentage points, according to the Statistical Centre of Iran.