The Iranian opposition movement is planning to take to the streets Thursday for what are expected to be the largest demonstrations since December's protests on the Shiite holy day of Ashura, in which eight people were killed. Thursday marks the 31st anniversary of the Iranian Revolution, and opposition leaders Mir Hossein Mousavi and Mehdi Karroubi have both urged a mass turnout by their supporters in what is known as the Green Movement. The anniversary has traditionally been promoted as a day of celebration by the country's leaders.
As the New York Times reported Wednesday, Iran's security officials have recently "unleashed an epidemic of arrests" in hopes of minimizing the impact of the opposition movement, particularly with regard to the anniversary. On Wednesday, Iranian authorities drastically reduced internet service in the country, cut off text messaging services and even cracked down on Google.
On Wednesday night, people in Tehran could be heard shouting "Allahu Akbar" (God is Great) in anticipation of Thursday's protests.