TEHRAN, Iran (CNN)  -- Marching in dramatic silence, many with tape over their mouths, hundreds of thousands of Iranians kept alive public support for opposition leader Mir Hossein Moussavi Wednesday even as the government stepped up efforts to thwart daily protests calling for a new presidential election.



Supporters of defeated reformist candidate Mir Hossein Moussavi line the streets of Tehran Wednesday.



Large crowds gathered in Haft-e-Tir Square in central Tehran Wednesday evening for a fifth day of protests, according to witnesses. The demonstrators are demanding that officials throw out the results of the balloting Friday that kept hardline incumbent President Mahmoud Ahmadinejad in power.



More protests are expected Thursday after Moussavi, in a message on his Web site, called for an afternoon "ceremony of mourning," which he planned to attend.



Referring to those who have died or been wounded "as a result of illegal and violent clashes" with his opponents, Moussavi urged people to gather in mosques and holy sites and wear "mourning symbols" in a show of sympathy and support for the families.



The protests have claimed at least eight lives, according to Iran's government-funded Press TV. The eighth death was included in a report the Intelligence Ministry provided to parliament Wednesday, the network said.  View a map of major rallies in Tehran »



The National Security and Foreign Policy Commission of the Iranian Majlis briefed lawmakers "about the current situation in the country," Press TV reported. No details of the report have been made public.



Iran is also investigating reports of violence at a Tehran University dormitory in the wake of rallies sparked by last week's disputed election.



Moussavi and former President Mohammad Khatami sent a joint letter asking Iran's courts to quell post-election violence and release protesters who have been arrested. The letter, posted on Moussavi's Web site, said, "the use of violence against ordinary people, raiding people's residences just because they chant the sacred phrase of Allh-o-akbar (Allah is great), beating up women and men, destroying buildings" is not in line with the standards of the Islamic Republic.



For a second day Wednesday, pro-Moussavi marchers urged their peers to march silently -- perhaps as a way of keeping a low profile in the face of riot police, witnesses told CNN.



Protesters held placards and posters reading, "Where is my vote?" and "Freedom," the witnesses said. Some held signs that said "Silence" and put their finger to their lips.



Several business owners reported that they closed up shop early so their employees could attend Wednesday's rally.



The government cracked down by banning international media from covering the protests and blocking access to Web sites.  Watch Christiane Amanpour on media restrictions »



A CNN iReporter who is not being identified said Wednesday's rally ended without incident.



"The people of Iran are finally fed up with the lies, the temperament, the foolish actions of Ahmadinejad," a 20-year-old Iranian man told CNN.



Authorities in Tehran transported dozens of protesters to jail Tuesday and blocked access to social networking sites such as Twitter and Facebook. The government accused international reporters of being the "mouthpiece" of "hooligans" who have created unrest, and said it could not guarantee the safety of those reporters. (Full story)



"I do believe them because the militia, they don't care who you are. If they see a camera, you will be a target," said a CNN producer who is not being identified for his safety. He was referring to the Basij, a volunteer paramilitary force that takes its orders from the Revolutionary Guard and is suspected of being behind most of the violent acts.



Citizens were barred from using typical means of getting Iran's stories to the outside world, but amateur videos and photos blossomed on sites such as YouTube and CNN's iReport. The content was impossible to verify in most cases, and much of it was posted anonymously or through third parties, some with little information. iReport.com: On the ground in Iran



Iran's Revolutionary Guard corps said it
What leader is supported in Tehran? Where do thousands protest?
Mir Hossein Moussavi Haft-e-Tir Square in central Tehran
question: What leader is supported in Tehran?, answer: Mir Hossein Moussavi | question: Where do thousands protest?, answer: Haft-e-Tir Square in central Tehran