The anonymous hacker group that brought down the websites of Visa and MasterCard Wednesday also attacked Republican Sarah Palin's website SarahPAC.com early on Thursday. The website remained inaccessible for hours following the attack, whcih was part of the group's Operation Payback.

While the credit card companies' website were again operating Thursday, SarahPac remained inaccessible.  

Media reports also suggested that the Swedish Government website was temporarily shut down after DDoS -- or distributed denial of service -- attacks. The group has been protesting the arrest of whistleblower Julian Assange. Hackers worldwide vowed to bring down websites of organizations that severed ties with or criticized Wikileaks, Assange's web organization.

Sarah Palin, the former governor of Alaska and vice-presidential candidate, last week called on the Obama administration to hunt down Assange like an al-Qaeda leader. She said that Assange was an anti-American operative with blood on his hands.

Assange is not a 'journalist,' any more than the 'editor' of al-Qaeda's new English-language magazine Inspire is a 'journalist, Palin, who is a darling of the tea party movement and contemplating a run for president in 2012, wrote on her Facebook page.

His past posting of classified documents revealed the identity of more than 100 Afghan sources to the Taliban. Why was he not pursued with the same urgency we pursue al-Qaeda and Taliban leaders?

Meanwhile, Twitter cracked down on the threat messages by the group posted on its site. Wikipedia, which also criticized Wikileaks over the recent diplomatic leaks, deleted the page of the Anonymous group.

A member of the hackers group told BBC's Today program on Thursday that the campaign is not yet over.

More and more people are downloading the voluntary botnet tool, said a person calling himself Coldblood.

The botnet tool enables users to launch multiple attacks on websites forcing them to be shut for a definite period. On Wednesday, websites of Visa, MasterCard and PayPal suffered such attacks after they announced that they had blocked transactions involving Wikileaks.

Coldblood also told the BBC that 'thousands of people had joined the war of data.'

We are trying to keep the Internet open and free but, in recent years, governments have been trying to limit the freedom we have on the Internet, he said.