'Operation Payback' targets Sarah Palin

A group of hackers known as "Operation Payback" has attacked the website and personal credit card account of former Alaska Gov. Sarah Palin (R) for speaking out against WikiLeaks and its founder, Julian Assange.

“No wonder others are keeping silent about Assange's antics,” Palin e-mailed ABC News. “This is what happens when you exercise the First Amendment and speak against his sick, un-American espionage efforts.”

ABC's Jake Tapper reported late Wednesday that Palin's SarahPAC was among the websites targeted by the group, along with Paypal, Mastercard and Visa, which all cut off payment services to WikiLeaks this week after facing pressure from U.S. authorities. A group of hackers known as Anonymous has claimed credit for the denial-of-service attacks.

Palin previously criticized Assange on her Facebook page, accusing him of outing Afghan intelligence sources to the Taliban. She urged the U.S. to pursue him with the same zeal as al Qaeda and the Taliban.

"Assange is not a 'journalist, any more than the 'editor' of al Qaeda’s new English-language magazine Inspire is a 'journalist.' He is an anti-American operative with blood on his hands," Palin wrote.

Assange, who is from Australia, is currently under arrest in London over allegations he sexually assaulted two Swedish women this summer. Assange has denied any wrongdoing and has said the accusations are part of an international plot to stop WikiLeaks.