Amateur footage believed to show opposition supporters demonstrating amid the Islamic Revolution anniversary celebrations in Iran, has been posted on YouTube.
In the first clip a riot policeman can be seen beating a semi-clothed man.
In the second clip protesters throw stones and chant "death to the dictator".
In the third video the demonstrators, some carrying a green flag, chant "Ya Hossein, Mir Hossein" in support of opposition leader Mir Hossein Mousavi.
They are believed to be near Saddeqiya Square, which is where another opposition leader Mehdi Karroubi was attacked earlier in the day.
The last video shows protesters thought to be at a Tehran underground railway station.
This video cannot be verified by the BBC.