The Egyptian government shut down most internet traffic in the country thirty minutes past midnight Thursday morning, in an effort to block communication prior to mass demonstrations on Friday. The shutdown came after the Associated Press published a camera-phone video of a demonstrator being shot to death by police.

The move constitutes an unprecedented restriction of internet communications. Other countries have blocked connections to specific websites, or attempted to slow down traffic, but have never succeeded in cutting off all internet access to the population.

Egypt has only four internet service providers, all of whom shut down service at around the same time. Traffic has reportedly remained open to the stock exchange and military, as the flagging regime attempted to prop up business confidence and repress the protests.

Mobile telephone service was also shut down, as Vodafone, the mobile phone service provider, cut service. “All mobile operators in Egypt have been instructed to suspend services in selected areas,” said the company, which operates jointly with the state telecom agency.

France Telecom, the owner of Mobinil, another Egyptian mobile phone company, said, “The Egyptian authorities have taken technical measures which prevent Mobinil from serving its customers,” adding that it had no information on when service would resume. The company added, “Under Egyptian legislation, the authorities have the right to issue such an order and we are obliged to comply with it.”

Renesys, the internet monitoring company, reported that 93 percent of internet addresses in Egypt remained offline on Friday. Their analysis showed that the internet shutdown was not “an instantaneous event on the front end; each service provider approached the task of shutting down its part of the Egyptian Internet separately.” The company concluded that the service providers received separate messages from the government asking them to shut down internet access.

The small subset of Egyptian internet services that remain online are reportedly tied to big business. Noor, one of the country’s four internet service providers is said to have kept some connections online, including those to the country’s stock exchange.

Renesys commented in a blog post that the events in Egypt constitute “a completely different situation from the modest internet manipulation that took place in Tunisia, where specific routes were blocked, or Iran, where the internet stayed up in a rate-limited form designed to make internet connectivity painfully slow.” The company added, “The Egyptian government’s actions tonight have essentially wiped their country from the global map.”

Not even the severe limits on internet traffic implemented by the Chinese government have come close to those of the Mubarak regime. While the Chinese government has cut off access to sites it deems subversive, users can bypass its restrictions by accessing proxy servers outside Chinese borders.

New forms of communication, including the micro-blogging platforms Facebook and Twitter, together with mobile text messaging services, have served as important communication tools for the popular uprisings in Egypt and Tunisia. The protests are led largely by young people who used the technologies to spread oppositional sentiments and coordinate protests.

The Egyptian government’s actions throw new light on attempts to introduce greater restrictions on internet traffic in the United States and other countries. In June 2010, Senators Joe Lieberman, Susan Collins, and Tom Carper introduced a bill that would give the US President power to shut down all or part of the internet indefinitely.

In promoting the law, Lieberman said, “Right now, China, the government, can disconnect parts of its Internet in a case of war. We need to have that here, too.” The senator is pushing to have the current version of the legislation voted on this year.

Commentators noted that, since the United States has hundreds of internet service providers, compared to only four in Egypt, shutting down internet connectivity in the US would be a far more difficult task, requiring significant preparation.

While the US government is certainly preparing such contingency plans in the event of social struggles, it has already taken overt steps to restrict internet activity. After WikiLeaks released its diplomatic cables, the US government cut off military access to the organization’s website and pressured US-based companies to block its use of servers and other technology.