Protesters, including university students, lorry drivers and gold merchants are said to be organising marches across the country under the umbrella of the country's Green movement, apparently inspired by recent demonstrations in Egypt and Tunisia.
The movement, also known as the Green Wave, made international headlines after the disputed 2009 presidential elections which saw Mahmoud Ahmadinejad win a second term in office.
Monday's protests have been called at the behest of Mir Hossein Mousavi and Mehdi Karroubi, both of whom were backed by the movement as opposition presidential candidates in the election two years ago. Read more