US Secretary of State Hillary Clinton has expressed her firm support for the thousands of opposition supporters who protested in Iran’s capital on Monday.
Mrs Clinton said they deserved to have “the same rights that they saw being played out in Egypt” and that Iran had to “open up” its political system.
One person was reportedly shot dead in the violent clashes between protesters and security forces in central Tehran.
Dozens were detained, and opposition leaders were placed under house arrest.
The BBC received reports of banned demonstrations in other Iranian cities, including Isfahan, Mashhad and Shiraz.