After a calm period in the Iranian markets, the Iranian rial has returned to drop against the dollar over the past two days.
Tehran Police Chief Brigadier General Hossein Rahimi announced the arrest of 20 active "brokers" in the dollar market.
There are more than 190 detainees on charges of selling dollars in light of the drop in the local currency, ISNA quoted Rahimi as saying.
Rahimi said police had closed the doors of unlicensed currency exchange offices in Ferdowsi Square in Tehran, which includes the country's largest currency exchange and banking offices.
He also vowed to chase those who spread incorrect exchange prices on social media.
The Iranian rial lost approximately 75 percent of its value and reached 190,000 rials in August before the government announced extraordinary measures to control the deterioration of the Iranian currency, including a security crackdown aimed at disrupting the economy.
