Iranian authorities have arrested several people accused of destroying photos of the Islamic Republic's revered founder and the current supreme leader at student demonstrations, state media reported Monday.

Tehran's prosecutor promised to show "no mercy" to those responsible, but the news reports carrying his remarks gave no details on those arrested.

In demonstrations on university campuses last week, supporters of Iran's pro-reform opposition movement burned and trampled on pictures of Supreme Leader Ayatollah Ali Khamenei. They oppose him for backing President Mahmoud Ahmadinejad's disputed June re-election, which the opposition says was rigged.

But the protesters have denied government claims they also tore up a photo of the leader of Iran's 1979 revolution, the late Ayatollah Ruhollah Khomeini, who remains a widely respected figure in Iran.

They accuse the government of staging video of someone destroying Khomeini's picture to discredit their protest movement and justify a continued crackdown.

Tehran Prosecutor Abbas Jafari Dolatabadi said authorities were preparing indictments against those arrested, according to the official IRNA news agency.

"There will be no mercy toward those who insulted the Imam (Khomeini) and top officials of the system," IRNA quoted him as saying.

Dolatabadi did not identify those arrested.

Reformists, including opposition leader Mir Hossein Mousavi, maintain their supporters had nothing to do with the burning of the supreme leader's picture, which they say is being used by the regime to discredit the opposition.

During the Dec. 7 rallies, student protesters shouted, "Death to the oppressor, whether it's the shah or the leader!" — making a daring comparison between Khamenei and the pro-U.S. shah, despised in Iran since his 1979 overthrow.