At least eight injured in unrest.
A huge fire has broken out at the notorious Evin jail in Iran's capital, where political prisoners and anti-government activists are held.
The state news agency says eight people were injured in the unrest.
It erupted after weeks of protests over the death of a woman in detention for "inappropriate attire".
MIddle East expert, Dr Sanam Vakil, says there are many reasons for the violence.