Iran on Thursday accused two opposition leaders of treason and vowed to block their ability to communicate with their supporters on the eve of a pro-regime "hatred" rally against them in Tehran.
The leaders, Mir Hossein Mousavi and Mehdi Karroubi, are under de facto house arrest but have regularly issued defiant messages to their supporters through their websites, including one which led to anti-government protests on Monday that left two people dead and several wounded.
The protests angered regime-backers and furious lawmakers demanded the execution of the pair, who were once pillars of the Islamic establishment.
"The treason committed by the movement of sedition leaders is not hidden from anyone," Iran's chief of judiciary Ayatollah Sadeq Larijani was quoted as saying by state news agency IRNA.
"This group which has rebelled against the religious government should know that while maintaining Islamic compassion we will not tolerate the establishment being compromised."
Larijani said steps were being taken by the judiciary against the two within the "framework of law," adding that the authorities were also targeting their communication networks.
"They (the people) should be certain that we will block the mechanism through which the sedition leaders issue their statements," he said, urging people to be patient and vigilant.
Mousavi and Karroubi have regularly issued anti-government statements on their websites and had called for a rally in support of Arab uprisings.
Heeding the call, thousands of their supporters took to Tehran streets on Monday and turned the gathering into a fresh anti-government demonstration which led to clashes with security forces and militiamen.
In the unrest two people were killed and several others wounded, including nine members of security forces, officials and opposition websites reported.
Similar but deadlier opposition protests that lasted several months in the wake of the the June 2009 disputed presidential election shook the pillars of Iran's Islamic regime and divided its elite clergy.
Dozens of people were killed, scores wounded and thousands arrested when authorities cracked down on those protesters, leading them to adopt, until Monday, a much lower profile.
With regime-backers baying for blood, the Islamic Propagation Coordination Council has called for a rally against the opposition on Friday.
Those joining the rally, the council said, will "scream out their hatred, wrath and disgust against the savage crimes and evil movements of sedition leaders, their Monafeghin (hypocrites) and their monarchist allies."
On Wednesday, Karroubi issued an Internet statement saying he was "ready to pay any price," while Mousavi in a similar way stated that Monday's protests were a "glorious achievement."
Tehran mayor Mohammad Baqer Qalibaf Thursday joined the rising chorus against the opposition leaders.
"The perpetrators (of protests) and specially the sedition leaders have neither religion nor brains," he said in an editorial in moderate-conservative Hamshahri newspaper.
"In the eyes of the noble Iranian nation, the crime of their actions is similar and equivalent to those who currently we know as Monafeghin," he said, referring to the banned group People's Mujahedeen of Iran.
Iranian officials have accused the United States, Israel and Britain of influencing the opposition chiefs.
On Tuesday, in what was one of his strongest statements backing Iran's opposition movement, US President Barack Obama, said that unlike in Egypt, Tehran's response to protests has been "to shoot people and beat people and arrest people."
"And, you know, my hope and expectation is that we're going to continue to see the people of Iran have the courage to be able to express their yearning for greater freedoms and a more representative government," he said.