New York (CNN) -- At least 12 people have been arrested as part of an ongoing operation targeting the notorious hacking collective known as Anonymous, a senior federal law enforcement official said Tuesday.

Up to 15 total arrests are expected, the official said, following the execution of more than 15 search warrants.

The warrants were being executed in New York and several other states Tuesday by the FBI as part of the investigation, according to a federal government official.

FBI agents spread out to about a half dozen locations on Long Island, in Brooklyn and in the Bronx, where they seized computers and other records, according to the official, who requested anonymity given the sensitivity of the investigation.

In the past, Anonymous has launched attacks on websites belonging to the Church of Scientology, the Motion Picture Association of America and the Recording Industry Association of America.

However, the hacker collective vaulted to worldwide fame in December, when it disabled or disrupted the websites of MasterCard, Visa and PayPal in what the group said was retaliation for the companies' cutting ties to the WikiLeaks website following the arrest of Julian Assange. Assange founded WikiLeaks, which facilitates the release of secret information. He is currently out on bail in England and is fighting extradition to Sweden, where he faces sex crime charges.

In addition, Anonymous has been linked to cyber attacks at the CIA, Sony, Fox News, the Arizona Department of Corrections and a well-known consulting firm, Booz Allen Hamilton, among others.

The group is implicated in denial-of-service attacks, in which large amounts of traffic are directed to a website, overloading it and, in effect, shutting it down.

The FBI in New York refused to confirm Tuesday's actions involved Anonymous. "These search warrants are being executed in connection with an ongoing FBI investigation," said FBI spokesman Peter Donald.

http://www.cnn.com/2011/CRIME/07/19/new.york.anonymous.warrants/index.html?hpt=hp_t2