Iranian security forces have been deployed throughout Tehran in response to the rally call issued by the opposition leaders MirHosein Mousavi and Mehdi Karroubi.
Reuters reports that security forces can be seen at all major arteries of the city. They have blocked the entrance to the subway along Valiasr Street, the main thoroughfare that runs north-south through the heart of the city.
The subway obstructions seem aimed at preventing people from getting to Imam Hossein Square, the march’s starting point.
Several eyewitnesses have reported that tear gas bombs are being used to scatter people and impede large gatherings.
Kaleme website says several thousand people have gathered in Engelab Square, and at the time of that report, the security forces had not confronted the crowds with any violence.
An eyewitness told Zamaneh that a gathering of about 5,000 people at Jamalzadeh Street was attacked by riot police, but no arrests were reported.
While official reports indicate that Mousavi’s home is under strict security with all communication cut off, Al-Arabiah earlier reported that Mousavi and his wife Zahra Rahnavard have joined the protesters.
State news agencies have completely ignored the thousands of people responding to the opposition’s call to rally.