A quickly growing jihadist group that used Facebook to spread its radical message has been shut down by the popular Web networking site after FOXNews.com alerted the company to the group's activities.

Facebook blocked the group, Fursan Ghazawat Alnusra — Arabic for "Knights in Support of the Invasion" — Thursday evening after the group swelled to about 120 members in just over one week.

The group had been exhorting its members to wage "Jihad to aid the religion of Allah and his Prophet."

• Click here to see the now-shuttered Web site of the jihadist group.

FOXNews.com, working closely with a former radical Muslim now dedicated to exposing cyberterror activity, was able to gain access to the group and its content.

• Click here to see photos of jihadist profiles from the site.

Fursan Ghazawat Alnusra wrote that its purpose was "to support Jihad and Mujihadeen" and that it started the Facebook group "to invade this Web site" and to ask "Allah to grant us Jihad and martyrdom."

It promised future action: "Today we invade your sites, tomorrow your lands and homes, o you cross worshippers."

The site's contents included three graphic videos:

— A so-called "martyr" statement from a soon-to-be homicide bomber;

— An Islamic militant, just before dying in battle, asking others to position him for proper prayer to bless his actions.

— A purported Egyptian "traitor" being beheaded on camera because he was accused of helping Americans in Iraq.

A few members of the group posted photos to identify themselves, known as profile pictures, that included well known members of Al Qaeda's leadership as well as prominent Saudi clerics.

One of the group's founders, who called himself Omar Abdel Hakeem, after the Syrian cleric who wrote the book on how to instruct Al Qaeda followers to use technology, wrote a mission statement to inspire "Jihad" against "the cross worshippers," or Christians:

"Maybe the day will come when one of the martyrs is asked [by Allah] who urged you to Jihad, so he answers saying: a message came to me from Facebook asking me to support the Mujihadeen. The message impacted me therefore I went to Jihad to destroy the places of the cross worshippers."

Jarret Brachman, a freelance cyberterror expert who formerly was director of research in the Combating Terrorism Center at the United States Military Academy, called the group's members "Ji-hobbyists" — users who may be passionate about Al Qaeda's teachings but were unlikely to take violent action.

"They're very knowledgeable and serious. They know the movement, and are using Facebook, not so much to plan an attack, but to propagate a message," Brachman said.

FOXNews.com contacted Facebook on Thursday seeking information about Fursan Ghazawat Alnusra. A few hours later, Facebook yanked the site. A similar group with the same content appeared briefly Friday and was taken down within minutes.

Facebook spokesman Barry Schnitt said the group is now disabled and that the company is investigating the group's "friends," and may take further action.

He said Facebook has taken steps to increase monitoring for content supporting terrorism, but he said such actions are difficult.

"Facebook is a start-up of 800 people with a user base of over 140 million," Schnitt said. "Certainly anything that supports violence is at the top of our monitoring list."

Though radical Islamic groups like Al Qaeda are pioneering uses of the Internet to train, share ideas and organize, cyber experts said the the most threatening Jihadists are reluctant to use sites like MySpace and Facebook.

"There is a major vulnerablility in using these sties. It is just an open way to support their movement," said Brachman.

To protect identities, members of Fursan Ghazawat Alnusra were told to use fake names and new e-mail accounts to avoid detection. Most of the discussions were carried out in Arabic, and there was an explicit appeal made for members who speak English, in order to help with English-language propaganda.

It was unclear how many members were based in the United States, although several members claimed to be Americans. According FOXNews.com's source who regularly monitored the group's discussions throughout the week, at least several of the members appeared to be American because of their writing style.

On Monday, the group announced on Facebook that it had created a formal structure of seven "battalions," responsible for duties ranging from spreading religious materials to military knowledge.

It claimed that three of the seven "battalions" had started recruiting, and communication among those individuals could continue even if the Facebook group were to shut down.

"We can't know if these are sophisticated actors capable of coordinating or assisting attacks or if these are just attention-seekers," warned terror expert David Draper of the Nine/Eleven Finding Answers (NEFA) Foundation. "But just having the propaganda available for impressionable youths to find at Facebook is dangerous in and of itself."

That idea seemed to be echoed by one Fursan Ghazawat Alnusra founding member, who identified himself as AboLbaraa Alshamy. He wrote:

"90% of this war is propaganda war.... Therefore those of us who are not in the real Jihad need to engage in this propaganda war."

Experts agree that moves by Facebook and other Internet companies to shut down the group do little. Members of the now-disbanded Fursan Ghazawat Alnusra could form a similar group on another social networking site or even again on Facebook.

They say that to avoid detection, groups like this know now know to strip out words that get their posts flagged, enabling them to get their message out to impressionable young Muslims.

"Propaganda doesn't need to have overt support for violence or terrorism in order to inspire someone to become a terrorist," Draper said.