US authorities arrested 16 people for cyber crimes including 14 over an online attack on the PayPal website claimed by the hacking group "Anonymous," the Department of Justice (DoJ) said.
The US indictment against the 14 hackers alleges the denial of service (DDoS) attacks on PayPal were "retribution" because the site terminated a donation account for the whistle-blowing group WikiLeaks.
Anonymous hackers called the PayPal attacks "Operation Avenge Assange," in reference to WikiLeaks founder Julian Assange, it said, adding that the US raids were coordinated with police in Britain and the Netherlands.
The Paypal attack suspects were arrested in raids in Alabama, Arizona, California, Colorado, Washington DC, Florida, Massachusetts, Nevada, New Mexico and Ohio, said a joint DoJ and Federal Bureau of Investigation (FBI) statement.
They conspired to "intentionally damage protected computers at PayPal" between December 6-10, 2010, it added.
The cyber attackers, who used alias including "Toxic," "Reaper," "Anthrophobic" and "No," were all expected to have appeared in court by the end of the day, in the districts where they were arrested.
Separately two suspects were arrested under similar indictments in Florida and New Jersey, while British police arrested one suspect and Dutch police four, it said.
In all FBI agents made 35 raids across the US as part of a probe into "coordinated cyber attacks against major companies and organizations," the FBI said, adding that to date more than 75 searches have been carried out.
Anonymous, an international hackers group, rose to fame with a series of attacks on websites linked to the Church of Scientology.
The group gained further prominence after launching retaliatory attacks on companies perceived to be enemies of the whistle-blowing website Wikileaks.
Anonymous sabotaged Turkish sites also last month to protest against Internet censorship.
After the December attacks US federal investigators followed a trail to Europe, Canada and back to the United States as they hunted down hackers who targeted "perceived corporate enemies of WikiLeaks."
The FBI traced Internet protocol addresses for the hackers to Canada and then back to California where a virtual server that was assigned one of the IP addresses used to launch the attacks was housed, media reports said.
A separate German probe into the pro-WikiLeaks attacks found that other commands to launch denial of service attacks on PayPal had come from an IP address assigned to a Texas-based company that hosts servers.
The FBI stressed that Tuesday's arrests were part of an "ongoing" investigation.
"Today's operational activities were done in coordination with the Metropolitan Police Service in the United Kingdom and the Dutch National Police Agency," said the US statement.
"The FBI thanks the multiple international, federal and domestic law enforcement agencies who continue to support these operations," it said.