WASHINGTON (NBC) — While Wikileaks founder Julian Assange remained jailed in London Wednesday, cyber forces loyal to him hacked into the websites of two credit card giants, and reportedly into SarahPac, the website of Sarah's Palin's political action committee.

The websites of Mastercard and Visa came under cyber attack along with Pay Pal and a Swiss bank after the four organizations all stopped processing donations to Wikileaks.

"It is like David versus Goliath.  It only takes a few people to have a significant impact on these major corporations, at least temporarily," explains MSNBC.com tech correspondent Bob Sullivan.

The credit card websites were inaccessible to online customers for parts of the day.

The attackers, activists who call themselves "Anonymous", essentially flooded the websites with armies of computers in an effort to knock the sites offline.

A "tweet" prompted the attack on Visa's website, calling for hackers to "fire their weapons".

The latest salvo in the cyberwar came from outspoken conservative Sarah Palin, who responded to NBC News' request for reaction to cyberattacks on her, reportedly from Wikileaks supporters.

Palin's email read: "No wonder others are keeping silent about Assange's antics.  This is what happens when he is exposed and you exercise your First Amendment rights and speak up against Assange's sick, un-American espionage efforts."

Despite international efforts to cut off funding to Wikileaks, the controversial site is growing exponentially, with hundreds of identical "mirror" sites keeping Wikileaks viable online.