Hacking group Anonymous claimed responsibility for targeting nearly 800 Twitter accounts, 12 Facebook pages and over 50 email addresses because of their links with ISIS.

Twitter (TWTR, Tech30) did not respond to a request for comment. Facebook (FB, Tech30) said it had shut down 11 of the 12 pages listed by Anonymous because they breached its rules. It declined to comment on whether it had been alerted to the offending content by the hackers.

Anonymous declared war against Islamic extremists last month, saying in a YouTube video that they would track down their websites and social media networks and take them down.

In a new video posted Friday, Anonymous sent another warning to ISIS: "You will be treated like a virus, and we are the cure. We own the Internet."

Checks by CNNMoney found the vast majority of Twitter accounts mentioned by Anonymous were displaying a message saying they had been suspended or were not available.

Both Twitter and Facebook are known to take down accounts and content that are associated with terrorism, but it can be difficult to keep track of their millions of users. They often rely on complaints from others before making a move.

Anonymous has gained notoriety over the last few years for hacking websites belonging to government departments, companies and other organizations.

Its campaign against ISIS was triggered by the bloody attack on French satirical magazine Charlie Hebdo in January, in which 12 people were murdered.

"We, Anonymous around the world, have decided to declare war on you the terrorists," it said in January.

ISIS -- an acronym for the Islamic State in Iraq and Syria -- started as an al Qaeda splinter group. It is fighting to create an Islamic state across Sunni areas of Iraq and Syria. It has taken over large swaths of northern and western Iraq and is known for carrying out public executions, crucifixions and other inhumane acts.

It has been known to recruit volunteer fighters via social media.

(CNN)