Iranian protesters poured into Tehran and several major cities in defiance of the Iranian government on Sunday, as large crowds gathered for Ashura, a major religious observance.

The crowds fought back security forces and chanted slogans against the Islamic regime. According to one opposition web site, at least four people were killed. While Iranian and international reporters were banned from the event, citizen media provided photos and video coverage.

A police base in Vali Asr Square is “conquered” by protesters:

And another demonstration in Tehran:

Photos on the Nakhana blog show people fighting back security forces:

And sign of victory:

Kosoof, a leading photoblogger, also covered the demonstration in Tehran:

Fearless people:

Marching together:

Sourced from: Global Voices Online