NIAC compiles the early reports:
According to Parleman News, scattered clashes have taken place between the security forces and protestors in Seven Tir Square in Tehran. The security forces have reportedly used tear gas several times while the number of protesters is increasing.
Mowj Camp reports that Tehran University students have left the university to join the demonstrations. According to Mowj Camp, anti-riot police has attacked the protesters who were going from the university to Seven Tir Square and there have been clashes in other parts of Tehran. Bullets were also shot in the air around Seven Tir Square.
Enduring America has more footage. Another clip after the jump:
The Guardian blog captions:
This one is appears to have been shot undercover so it is difficult to get a sense of what is going on, but the crowd can be heard chanting "don't be afraid, we are altogether" and "down with the dictator". Fires can also be seen burning in the streets - a sign that teargas has been used as the smoke weakens the power of the gas.