Iran's Supreme Leader on Tuesday accused enemies of the Islamic Republic of stirring unrest, as anti-government demonstrations that began last week continued.
"In recent days, enemies of Iran used different tools including cash, weapons, politics and intelligence apparatus to create troubles for the Islamic Republic," Ayatollah Ali Khamenei was quoted as saying in a post on his official website.
Khamenei said he would address the nation about the recent events "when the time is right."
Police have arrested more than 450 protesters in the Iranian capital Tehran over the past three days, the deputy provincial governor said on Tuesday, as a crackdown intensified against anti-government demonstrations that began last week.
Protesters also attacked police stations elsewhere in Iran late into the night on Monday, news agency and social media reports said.
One member of the security forces was reported killed on Monday, bringing to at least 14 the death toll stemming from the boldest challenge to Iran's clerical leadership since unrest in 2009.
Musa Ghazanfarabadi, head of Tehran's Revolutionary Court, warned protesters on Tuesday that those arrested would face harsh punishment.
The semi-official ILNA news agency quoted Ali Asghar Naserbakht, the deputy governor of Tehran province, as saying that 200 people were arrested on Saturday in Tehran, 150 people on Sunday and about 100 people on Monday.
Hundreds of others have been arrested in other cities, according to agency reports and social media.
Naserbakht said the situation in Tehran was under control and police has not asked for the help of the Revolutionary Guards special forces.