A representative of Iran's Supreme Leader Ayatollah Ali Khamenei has said opposition leaders were "enemies of God" who should be executed under the country's sharia law.
"Those who are behind the current sedition in the country ... are mohareb (enemies of God) and the law is very clear about punishment of a mohareb," Abbas Vaez-Tabasi, the representative of Khamenei, who possesses ultimate authority in Iran, said in a statement on Tuesday.
Under Iran's Islamic sharia law the sentence for "mohareb" is execution.
The statement coincided with rallies by tens of thousands of government supporters calling for opposition leaders to be punished for fomenting unrest after June's disputed presidential election, state media said.
Meddling
Earlier, Iran called on the British ambassador to respond to accusations of his government's "interference" in the Islamic Republic, as pro-government rallies continue.
Manouchehr Mottaki, the Iranian foreign minister, told a news conference that the ambassador had been summoned over Britain's interference in Iran's domestic affairs.
"If Britain does not stop talking nonsense it will get a slap in the mouth," he said.
Mahmoud Ahmadinejad, the president, also said that recent opposition rallies in the country are "masquerade" backed by the US and Israel.
The UK said that the envoy would be robust in the face of any Iranian criticism and reiterate that Tehran must respect human rights.
The summons came hours after the Revolutionary Guards security force said opposition groups were working with Tehran's foreign enemies, implicating London.
Iran's primary reformist party has said that the government is not respecting Iranian law in battling opposition protesters.
"The Green Movement is peaceful and law-abiding. It avoids any violence and will press ahead on its path," the Islamic Iran Participation Front (IIPF) said in a statement carried by an opposition website.
"The IIPF condemns attacks on defenceless people and believes the incidents after the presidential election and especially on Ashura indicate the complete failure of the coup d'etat and not the strength of government."
State television reported that tens of thousands of people rallied nationwide in support for the government of Ahmadinejad, stating that the demonstrations had taken place spontaneously.
'Maximum punishment'
Earlier, Iranian MPs called for opposition protesters arrested following clashes with police on Sunday to face the "maximum punishment" allowed by law.
Hundreds of people were arrested as fierce battles were fought on the streets of the capital Tehran.
Many more, including aides to opposition leaders and pro-reform clerics, have reportedly been detained since.
Shirin Ebadi, the country's Nobel prize-winning human rights activist, said on Tuesday that her sister was among those arrested.
Intelligence officers reportedly raided Dr Nooshin Ebadi's house as part of its sweeping clampdown on the country's opposition.
"My sister Dr Nooshin Ebadi was arrested at 9pm [16:30 GMT] on December 28 by four intelligence agents at her home and sent to prison," Ebadi said in a statement carried by the opposition Rahesabz website.
"I am not aware of the place of her detention or the reason for her arrest."
'Counter-revolutionaries'
MPs accused the protesters, who poured onto the streets in the latest display of anger at the disputed presidential election in June, of being "anti-religion" and "counter-revolutionaries".
Ali Larijani, the parliamentary speaker, said the legislative body "wants the judiciary and intelligence bodies to arrest those who insult religion and impose the maximum punishment on them without reservation".
He also said parliament condemned "disgusting comments" of foreign governments after Sunday's unrest.
Barack Obama, the US president, has called on Monday for Iran to release those rounded up in the crackdown and "to respect the rights of its own people".
Larijani responded on Tuesday saying Obama should be more concerned about "the behaviour of his troops in Guantanamo, Abu Ghraib, Afghanistan and Iraq".
"Your admiration for the opposition movement protesters will ruin your reputation and will also reveal where the movement of this anti-religious group is linked to," he said, reading from a statement prepared on behalf of the Iranian parliament.
Tear gas
Clashes broke out after police used teargas, batons, and eventually live rounds to try to disperse thousand of protesters.
Muhammad Sahimi, an Iran expert at the University of Southern California in the US, said the government's crackdown was unlikely to stop the opposition.
"If they were going to be cowed, they should have been by now," he told Al Jazeera.
"Over the past six months, violence has been used, a lot of people have been arrested, tens of people have been killed, but yet you don't see any decrease in the level of demonstrations," he said.
Sahimi said that as the government sought to suppress the movement by force, support for the opposition instead grew, expanding across the country.
"The demands have gone way beyond cancellation of elections, and now people are demanding fundamental change in the system" of government, he told Al Jazeera.
"The goal right now, is at the minimum, to weaken the position of [Iran's ] supreme leader, to make him sort of a figure head ... if not outright elimination of the supreme leader, and the writing of a new constitution."
Source: Al Jazeera
