Twitter and Facebook have also deleted accounts believed to be affiliated with Anonymous
Dutch authorities have arrested a 16-year-old boy in relation to the cyberattacks against Visa, MasterCard and PayPal, which were aimed at punishing those companies for cutting off services to WikiLeaks.
The boy was arrested in The Hague, and he will be arraigned before a judge on Friday in Rotterdam, according to a press release from the Netherlands' Public Prosecution Service. The boy, whose computer equipment was seized, has allegedly confessed to taking part in the attacks.
The Public Prosecution Service said he is likely part of a larger group of hackers.
The arrest follows a series of distributed denial-of-service (DDOS) attacks aimed at websites that have been critical of WikiLeaks, which has been releasing portions of 250,000 secret US diplomatic cables since late last month. The attacks seek to overwhelm websites and services by sending streams of meaningless traffic.
Part of the attacks originated in the Netherlands and the main site coordinating the attacks, anonops.net, was hosted in a Dutch data center in Haarlem. The site is down since police actions Wednesday.
Right after the police found out that there were cyberattacks coming from the Netherlands, the Team High Tech Crime started an investigation, the Dutch attorney general reported.
The attorney general also noted that "probably thousands of computers" took part in the attacks. The police are still investigating and will probably arrest more people.
Since the release of the documents began, several companies have decided to cut WikiLeaks off from their services, including PayPal, MasterCard, Visa and the Swiss payment transaction firm PostFinance, where WikiLeaks founder Julian Assange held an account.
In response, a loose affiliation of hackers called Anonymous have orchestrated DDoS attacks against those websites over the past two days or so, knocking many of the sites offline. The group has dubbed that effort "Operation: Payback." Other websites that have been attacked include those of vocal critics of WikiLeaks, including US Senator Joseph Lieberman and former Alaska Governor and vice presidential candidate Sarah Palin.
Twitter and Facebook have also deleted accounts believed to be affiliated with Anonymous.
On Thursday, BBC Radio 4 broadcast an interview with a 22-year-old who goes by the nickname "Cold Blood" and claims he is part of Anonymous. Cold Blood, who appeared in the BBC's studios, said that more people were downloading a botnet tool that enables them to perform a DDoS attack.
The campaign is aimed at companies that have decided not to deal with WikiLeaks, Cold Blood said, and is also a protest against what Anonymous believes is increasing control over the Internet by governments and the European Union.
"We are trying to keep the Internet open and free for everyone," said Cold Blood, who described himself as a software engineer.
WikiLeaks and its founder and editor Assange have come under fierce criticism from U.S. government officials and politicians for releasing the information, which is believed to have been leaked to the site by US Army Private Bradley E. Manning.
Manning has been charged with mishandling and transferring classified information in connection with the cables and a video of an Apache helicopter shooting civilians in Iraq.