Cyber activists striking at companies seen as enemies of WikiLeaks sought to block the website of online payment firm Moneybookers on Friday but denied their campaign was intended to damage economic activity.

Some activists communicating on Internet channels also called for attacks on official Dutch websites following the arrest in The Hague on Thursday of a 16-year-old boy suspected of involvement in the online campaign.

The attack on Moneybookers appeared to have blocked the site for about two minutes at about 1235 GMT but it subsequently came back online. The hackers pledged to continue their assault.

If we don't panic, and we get bigger, no one can stop us, wrote a participant in a chat room used by what the activists call the Operation Payback campaign.

A string of U.S. institutions has ended services to WikiLeaks after the website published thousands of secret U.S. diplomatic reports that have caused strains between Washington and several allies.

Online retail and web-hosting powerhouse Amazon last week stopped hosting WikiLeaks' website, and on Thursday it briefly became the main target of the pro-WikiLeaks campaigners -- before they admitted it was too big for them, for the moment.

Activists said Moneybooks had became a target because it had informed WikiLeaks in August it had closed its account with the service to comply with investigations by several governments into possible money laundering and other matters.

There was no immediate response to a request for comment from Moneybookers.

AVERAGE INTERNET CITIZENS

In a statement, the activists, who collectively call themselves Anonymous, said they were not hackers but rather average Internet Citizens.

We do not want to steal your personal information or credit card numbers. We also do not seek to attack critical infrastructure of companies such as Mastercard, Visa, PayPal or Amazon, the statement said.

The point of Operation Payback was never to target critical infrastructure of any of the companies or organizations affected. Rather than doing that, we focused on their corporate websites, which is to say, their online public face.

It is a symbolic action ... Our current goal is to raise awareness about WikiLeaks and the underhanded methods employed by the above companies to impair WikiLeaks' ability to function.

The statement appeared to have been published several hours after one by WikiLeaks which said the website had no links to the cyber attacks and neither supported nor condemned them.

The statement quoted WikiLeaks spokesman Kristinn Hrafnsson as saying the attacks were a reflection of public opinion on the actions of the targets.

Some freedom of information campaigners sympathetic to WikiLeaks look askance at the attacks, saying its cause cannot be furthered by denying freedom of information to others.

THE GAME HAS CHANGED

The teenage boy in the Netherlands was arrested by a high-tech crime unit after admitting to attacks on the websites of two credit card companies, MasterCard and Visa, the prosecution in the Netherlands said on its website.

The boy, whose details were not disclosed, was due to appear in court in Rotterdam on Friday afternoon.

He was believed to be part of a larger group of hackers under investigation that participated in so-called denial of service attacks, the prosecution said. Data and computer equipment were confiscated during his arrest.

On one Internet communication service used by the online campaign, several participants debated whether to end the attacks and instead focus on discovering more embarrassing material in the leaked documents.

We have at best given them a black eye. The game has changed. When the game changes so must our strategies, read a suggestion which proposed Operation Leakspin.

The idea would be to get hold of unreported stories buried in the thousands of cables and post snippets of them all over the Internet, the participant said.

(Additional reporting by Georgina Prodhan in London, Marius Bosch in Johannesburg)

(Writing by William Maclean; editing by Philippa Fletcher)

Wikileaks Target