Iran accused the United States of "intolerable" meddling Wedneday and continued its crackdown on the media as thousands of protesters took to the streets in growing defiance of the country's disputed election results.
The crackdown on the demonstrators seems to be having the opposite effect, as the scope of the protest is challenging the very heart of Iran's Islamic regime.
While experts say an overthrow of the system is unlikely, the messy election has brought Supreme Leader Ayatollah Ali Khamenei and the ruling clerics into the public discourse in an unprecedented fashion.
"It's changing the way Iranians see the supreme leader and the system in general," Meir Javedanfar, an Iranian affairs analyst told The Associated Press. "That opens up they system up in ways it's never faced before."
Despite a muted response from U.S. President Barack Obama compared to other countries' criticisms, Iran says Washington is helping to incite the current feud between supporters of pro-reformist Mir Hossein Mousavi and re-elected President Mahmoud Ahmadinejad.
According to Iranian state television, Iran summoned the Swiss ambassador, who represents the U.S. in Iran, to complain about interference from the Americans.
After the 1979 Islamic Revolution, Iran and the U.S. broke off diplomatic relations and they never resumed.
Meanwhile, thousands of Mousavi supporters marched again on Wednesday.
His supporters have been protesting daily since the reformist lost last week's election to Ahmadinejad.
Mousavi has accused the government of rigging the election in favour of Ahmadinejad.
On Thursday, Mousavi has called for a massive rally to be held in Tehran. He called for his supporters to wear black to remember those who have been shot and killed during the protest.
Seven people were shot and killed in the crackdown against protesters on Monday.
Opposition supporters have used websites like Facebook and Twitter to organize rallies and to get the message out about what's going on inside the country.
The websites have become an even more important source of information since the government barred foreign media Tuesday from leaving their offices to cover the demonstrations.
The Iranian government has blocked Twitter, Facebook and a number of other websites, but tech-savvy protesters are finding ways around that.
Alfred Hermida, a professor at the University of British Columbia, told CTV's Canada AM that Mousavi has used websites like Twitter as a virtual press office.
He said Mousavi's camp is able to use the website for "talking about their activities, talking about their plans and also informing their supporters of what is true and what isn't true."
In response Wednesday, Iran's Revolutionary Guard, an elite military force, warned website and blog operators to remove any materials that could "create tension."
The Guards, which answer to Khamenei, are one of the main sources of power for the cleric-led government.
On Tuesday, as tensions mounted, the unelected supreme leader made an unusual appeal to Iranians, telling them to keep believing in the system even if they disagree with the election results.
Iran's Guardian Council, an unelected body of 12 clerics and Islamic law experts, also said they were prepared to hold a limited recount of ballots at locations where candidates alleged voting irregularities occurred.
Despite the announcement, Mousavi called the election an "astonishing charade" and called for it to be held again.
Reformist cleric Ali Akbar Mohtashamipour, who represents Mousavi, said eventually the people's voice will be heard.
"If the whole people become aware, avoid violent measures and continue their civil confrontation with that, they will win. No power can stand up to people's will," Mohtashamipour said. "I do not think that the Guardian Council will have the courage to stand against people."
Meanwhile, thousands have also been demonstrating in support of Ahmadinejad.
"This nation will protect and defend its revolution in any way," Gholam Ali Haddad Adel, a prominent lawmaker and Ahmadinejad supporter, told the pro-government crowd in Vali Asr Square.
With files from The Associated Press
