Iran's Revolutionary Guards have warned anti-government protesters they will face the nation's "iron fist" if political unrest continues.
Three days of demonstrations erupted over falling living standards.
But a Revolutionary Guards commander said the protests had degenerated into people chanting political slogans and burning public property.
They are the biggest show of dissent since huge pro-reform rallies in 2009. There are reports of two deaths.
There were calls for the removal or death of Iran's Supreme leader, Ayatollah Ali Khamenei, in the cities of Khoramabad, Zanjan and Ahvaz.
Iran's Islamic Revolutions Guards Corp is a powerful force with ties to the country's supreme leader, and is dedicated to preserving the country's Islamic system, reports BBC.
Brigadier-General Esmail Kowsari told the ISNA news agency: "If people came into the streets over high prices, they should not have chanted those slogans and burned public property and cars."
Iran's interior minister has also warned the public to avoid "illegal gatherings".