Iranian security forces, including the pro-government Basij militia, are trying to quell growing nationwide protests that erupted after a woman died in the custody of the morality police last week.
Four members of the Basij were killed in the unrest, including one who was stabbed, Iranian media said.
Here are some facts about the Basij, shock troops which have been at the forefront of repressing popular unrest, making them a direct target for protesters angered by the lack of political and social freedoms in Iran.
