Agents with the Federal Bureau of Investigation, in conjunction with Scotland Yard, executed more than 40 search warrants as part of an ongoing investigation into cyber attacks on major corporations throughout the United States on behalf of WikiLeaks, the FBI tells FOX Business.

The United Kingdom’s Metropolitan Police Service also executed additional search warrants and arrested five people for their alleged role in the attacks, the FBI says.

WikiLeaks has said it has no official connection to the group that calls itself “Anonymous,” which allegedly carried out retaliatory cyber attacks on Visa (NYSE:V), MasterCard (NYSE:MA) and PayPal after these companies cut off services to WikiLeaks. WikiLeaks is a website that posts leaked documents from companies and governments. It recently posted confidential cables from the U.S. State Dept. as well as military documents on the wars in Afghanistan and Iraq. The FBI says the group calling itself “Anonymous” has claimed responsibility for the attacks.

The FBI says such attacks, called distributed denial of service attacks [DDoS], are illegal and can carry prison sentences of up to 10 years as well as “significant civil liability.”

The cyber attacks are deployed via software called “Low Orbit Ion Canon” tools that hack into systems and are “designed to damage a computer network’s ability to function by flooding it with useless commands and information, thus denying service to legitimate users,” the FBI says.

“Anonymous” also allegedly made the software tools available for free download on the Internet, the FBI says.

The FBI says it is also working closely with its international law enforcement partners and others to mitigate these threats. Authorities in the Netherlands, Germany, and France have also taken their own investigative and enforcement actions, the FBI notes.

And a public-private partnership, the National Cyber-Forensics and Training Alliance [NCFTA] also is providing assistance, the FBI says.

Law enforcement officials note that the NCFTA has advised that software from any untrustworthy source “represents a potential threat and should be removed.” Major Internet security (anti-virus) software providers have instituted updates so they will detect the so-called “Low Orbit Ion Canon” tools used in these attacks, the FBI adds.