Several Iranian government Web sites became inaccessible earlier this week amid the violent protests decrying what activists claimed were fraudulent elections. But whether the coordinated denial of service attack was ultimately successful has not yet been confirmed.

Blocked government Web sites following the protests included leader.ir, ahmadinejad.ir and iribnews.ir. However, some of the targeted Web sites were up and running by Wednesday evening.

According to a Wired blog, pro-democracy activists galvanized supporters into action by asking them to use simple hacking tools to flood Iranian government Web sites with junk e-mail.

In particular, micro-blogging site Twitter was used as one of the main vehicles of communication to propel the revolution. The San Francisco-based Twitter was forced to reschedule a planned maintenance earlier this week in order to keep the channel of communication open for Tweeters sending information to and from Iran.

Meanwhile, "Green Revolution" supporters also used the San Francisco-based site to effectively overwhelm the country's networks with traffic in a concerted denial of service attack. The action was apparently intended to bring down an array of Iranian government Web sites to protest Iran's election, according to security experts.

One activist Tweeted "NOTE to HACKERS—attack www.farhang.gov.ir--pls try to hack all iran gov wesites. (sic) Very difficult for us,'" Wired reported.

Security researchers say that the denial of service attack was executed when Iran's fragile Internet infrastructure was choked with a flood of traffic which overwhelmed Iran's fragile Internet infrastructure.

Unlike U.S. Web infrastructure, the Iranian government supports a centralized network, which affects Internet access for the entirety of the country and can become unstable with minor disruptions, experts say. The centralized architecture allowed the hackers to easily flood the network and essentially block numerous Web sites, security researchers said.

Security bloggers say however, that despite the cause, any coordinated disruption of the Internet could potentially affect Internet access for the entire country and ultimately serve to work against the very people it was supposed to help by denying them a needed avenue of communication. Other bloggers say the coordinated attack could fan the flames by giving the Iranian government a tangible rationale for crushing the opposition.

"People are really valuing keeping the Internet up and functioning. It's not such a great idea, when thing are overloaded," said Paul Ferguson, advanced threat researcher for Trend Micro. "There're a lot of innocent victims along that path."

Ferguson said that the security community would likely see more denial of service and other coordinated cyber attacks to further high-profile political causes, as more individuals gain both expertise as well as access to basic hacking tools.