LONDON — WikiLeaks supporters struck back Wednesday at perceived enemies of the site and its jailed founder Julian Assange, launching hack attacks against MasterCard, Swedish prosecutors, a Swedish lawyer and a Swiss group that froze Assange's bank account.
So-called hacktivists operating under the label "Operation Payback" claimed responsibility in a Twitter message for causing technological problems at MasterCard, which pulled the plug on its relationship with WikiLeaks on Tuesday.
MasterCard said it was "experiencing heavy traffic," but spokesman James Issokson told The Associated Press the company would not confirm whether WikiLeaks was involved. Issokson said MasterCard was trying to restore service Wednesday but was not sure how long that would take. The website's technical problems have no impact on consumers using credit cards for secure transactions, he added.
MasterCard is the latest in a string of U.S.-based Internet companies — including Visa, Amazon.com, PayPal Inc. and EveryDNS — to cut ties to WikiLeaks in recent days amid intense U.S. government pressure.
Visa said it was having no technological problems Wednesday.
The online attacks are part of a wave of support for WikiLeaks that is sweeping the Internet. Twitter was choked with messages of solidarity for the group, while the site's Facebook page hit 1 million fans.
Offline, the organization is under pressure on many fronts. Assange, who turned himself in to London police on Tuesday, is now in a British prison fighting extradition to Sweden over a sex crimes case. Moves by Swiss Postfinance, MasterCard, PayPal and others, meanwhile, have impaired the secret-spilling group's ability to raise money.
Undeterred, the group released more confidential U.S. cables overnight.