Clashes meanwhile erupted between regime backers and "apparent" supporters of the opposition at a funeral attended by thousands in Tehran of a student killed in anti-government protests of Monday, state television reported.
Iran's prosecutor general Gholam Hossein Mohseni Ejeie warned that action would be taken against opposition leaders Mir Hossein Mousavi and Mehdi Karroubi, who reject the presidency of Mahmoud Ahmadinejad and who had called for Monday's demonstration which turned deadly.
"The heads of seditions are the people who should be punished for their criminal acts and God willing actions in this regard are being taken," Mohseni Ejeie said, according to Fars news agency.
"People have given them their punishment, but people also have a legitimate right to demand (punishment) from the judiciary which we hope we would be able to fulfill."
Mohseni Ejeie said several people were arrested during Monday's protests but some were immediately released, adding that some more arrests were expected.
"In general the anti-revolution current is behind these events. Unfortunately, some have fallen in traps of America," he said. Iranian officials accuse the United States, Britain and Israel of influencing the opposition movement.
Thousands of anti-government protesters took to streets of Tehran Monday and clashed with riot-police in which two people were killed -- including the student buried on Wednesday -- and several wounded, officials and opposition websites say.
Among the wounded were nine members of the security forces, one of whom was seriously hurt.
The protest, initially held under the pretext of showing solidarity with Arab uprisings, were the first anti-government demonstration since February 11, 2010 when similar agitation was crushed by security forces and militiamen.
But Karroubi and Mousavi came out fighting on Wednesday, issuing statements slamming the authorities and praising demonstrators, after lawmakers the previous day demanded they be executed for their role in Monday's protests.
Karroubi said in a statement posted on his website Sahamnews.org, he was ready to "pay any price."
"I declare that I am not afraid of any kind of threat and as a soldier of this great nation for the past almost 50 years, I am ready to pay any price," he said.
"I am warning that before it is too late, take out the buds from your ears and listen to the voice of the people. Forcing violence and opposing peoples' wishes will last only for a certain time," the cleric said.
In a separate statement on his own website Kaleme.com, Mousavi criticised the authorities and praised the protesters for Monday's rally.
"The glorious rally on 25th Bahman (February 14) is a great achievement for the great people of a great nation and for the Green Movement," Mousavi said, referring to the opposition movement and its supporters who took to streets on Monday.
Tension sparked by Monday's protests continued to ripple on Wednesday when according to reports regime backers clashed with opposition supporters at Wednesday's funeral.
"Students and people participating in the funeral of martyr Sane'e Zhale in Tehran Fine Arts University are clashing with a few apparently from the sedition movement," the state television website said.
Zhale, a Sunni Kurd, became the centre of a dispute Wednesday, with regime-backers insisting he was member of the volunteer Islamist Basij militia, while the opposition said he came from their ranks.
"This university student (Zhale) was shot around Enghelab Square by small arms fire. He was a student of fine arts and defender of the regime," said state news agency IRNA.
Opposition website Rahesabz.net said Zhale was "pro-Mousavi and a member of the Green Movement," referring to the opposition movement.
"His family was under pressure to say he is Basiji and pro-government," the website said.
Sajjad Rezai, a student activist at the fine arts university, said Basiji militiamen who came in "tens of buses .... sought to provoke students Wednesday but failed," Kaleme.com said.