Iranian anti-government student protests continued on Sunday as debate raged over television images showing the burning of a photo of the revered Ayatollah Ruhollah Khomeini, the founder of the Islamic republic.

Iran's supreme leader, Ayatollah Ali Khamenei, called for calm amid the anger over the images, even as he indirectly accused the opposition of creating an environment to allow such an incident to happen.

State television has repeatedly shown a film clip, ostensibly taken during opposition protests on Dec. 7, of unidentified hands burning the picture of Khomeini, who remains widely respected in the country.

"Some have converted the election campaign into a campaign against the entire system," Khamenei said without naming any opposition leaders. "We call on those who are angry to remain calm."

Reformists, including former presidential candidate Mir Hossein Musavi, maintain that their supporters had nothing to do with the burning of the picture, which they say is being used by the regime to discredit the opposition.

Dozens of police surrounded the campus of Tehran University as inside hundreds of pro-reform students protested against the accusations. The students contend the images were fabricated by government agents and are being used to justify further crackdowns on the opposition.

The elite Revolutionary Guard, the country's most powerful military force, called on Sunday for the trial and punishment of those behind the move, as it continues to pressure the opposition.

"The Revolutionary Guard ... won't tolerate any silence or hesitation in the immediate identification, trial and punishment of those carrying out this ugly insult and the agents behind them," it said in a statement posted on its Web site.

Under the law, insult to the late or current supreme leader can lead to two years of prison.

The Guard, which is tasked with defending the clerical regime that came to power in Iran in 1979 under Khomeini's leadership after the pro-U.S. shah was overthrown, was at the forefront of squashing Iran's post-election unrest.

Reformists contend that President Mahmoud Ahmadinejad was re-elected in fraudulent June contests and for months protested against the government before widespread crackdowns.

The Dec. 7 rallies did see numerous attacks on the current supreme leader of the country, Khamenei.

Students chanted slogans against him, burned and trampled his photos in unprecedented acts of defiance in a country where Khamenei has final say in all state matters.

The actions of the students reflect how a protest movement that began by rejecting President Mahmoud Ahmadinejad's June 12 re-election has evolved to confront the country's ruling theocracy.