Suspects accused of "acts of sabotage", including murdering security guards and arson, face open mass trials this week.
Authorities have not said how many have been arrested nationwide, but rights activists have put the total at 14,000.
The announcement came as two teenage protesters allegedly killed by security forces were buried in north-east Iran.
Kumar Daroftateh, 16, was shot at close range at a demonstration in the city of Piranshahr and died in hospital on Sunday night, according to Kurdish human rights group Hengaw.
At his funeral on Monday, mourners shouted slogans against the government.
Kurdish activists said Kumar Daroftateh, 16, was shot by security forces at a protest in Piranshahr
To the south, in the city of Sanandaj, another crowd gathered at the grave of Sarina Saedi, who was also 16.
The BBC's Kasra Naji says witnesses saw her fall to the ground during a protest a few days ago after she was hit by birdshot fired by security forces.
However, our correspondent adds, Sarina's father was forced to announce on TV that her death was the result of a suicide in order to absolve security forces of blame.
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