Azizollah Rajabzadeh, a security spokesman, said 62 of those detained have been handed over to judicial authorities for trial and the rest have been released after questioning.
"Police detained 109 people who disturbed public order on the sidelines of the rally," he said. "62 of those arrested were handed over to judicial authorities and the rest were set free. Of 62 detained, 43 are men and 19 women."
Iranian security forces beat anti-government protesters with batons Wednesday on the sidelines of state-sanctioned rallies to mark the 30th anniversary of the U.S. Embassy takeover.
The counter-demonstrations were the opposition's first major show of force on Tehran's streets in nearly two months.
The protests showed the determination of Iran's opposition to reassert its voice. But the latest marches drew far fewer demonstrators than in the summer or even in September, suggesting the relentless pressure by authorities could be taking a toll.
Three journalists are reportedly among those detained. Farhad Pouladi, a reporter for the news agency Agence France Presse, and two other foreign jouranlists were taken into custody Wednesday as they headed to cover rallies outside the former U.S. Embassy.