Students and activists say some of those who have spoken out against hard-line President Mahmud Ahmadinejad and his government have been detained or blacklisted from university courses.
Ahmadinejad and his government insist they support free speech and welcome constructive opposition.
"Police arrested 10 student activists for staging an illegal protest in front of parliament," Fars said. "The students -- two women and eight men who claimed to be banned from enrolling at universities -- were taken away by a police minibus."
Fars did not say where they were being held. The report could not be confirmed independently and was not carried by other news agencies.
Most of Iran's pro-democracy student leaders have in recent years fled the country or have been jailed.
Rights activists say other dissenting voices, including labor movement figures and intellectuals, have also been targets of the crackdown.