Tehran's main bazaar has been closed as the government tightens controls trying to halt the fall of the currency after it hit a record low.
The semi-official Mehr news agency said the bazaar - the traditional commercial hub in Iran's capital - was closed for security reasons.
Iranian officials have faced increasing public anger over the plummeting rial and rising prices, blamed partly on Western sanctions over Tehran's nuclear programme.
Mehr said Ahmad Karimi Isfahani, a bazaar official, denied reports that merchants staged a protest.
Police are patrolling streets where freelance money dealers work. Exchange shops are closed.
The rial hit 34,500 against the US dollar on Tuesday on the unofficial street trading rate. Two years ago, it was close to 10,000 rials for the dollar.