LONDON - More cyber attacks in retaliation for attempts to block the WikiLeaks website are likely in a "data war" to protect Internet freedom, a representative of one of the groups involved said on Thursday.
Swedish newspaper Aftonbladet said the Swedish government's website was down for a short time overnight in the latest apparent attack. Sweden has issued an arrest warrant for WikiLeaks' founder Julian Assange over sex crimes and he is in jail in London, awaiting an extradition hearing.
WikiLeaks has angered the U.S. authorities by starting to release details of 250,000 confidential diplomatic cables.
Assange, a 39-year-old Australian, has been hailed as an advocate of free speech by supporters, but now finds himself fighting serious sexual allegations made by two women in Sweden.
Assange will have another court appearance next Tuesday and his supporters assert he is being victimised for his work.
Online collective Anonymous appears to be using social networking site Twitter to coordinate attacks on websites belonging to entities it views as trying to silence WikiLeaks.
"Anonymous has targeted mainly companies which have decided for whatever reason not to deal with WikiLeaks. Some of the main targets involve Amazon, MasterCard, Visa and PayPal," a spokesman calling himself "Coldblood" told BBC Radio 4.
"The campaign is not over from what I've seen, it's still going strong. More people are joining, more and more people are downloading the voluntary botnet tool which allows people to command dos (distributed denial of service) attacks," he added.
The speaker, who had an English accent, said he was aged 22 and was a software engineer.
MORE SECRET CABLES RELEASED
Wikileaks is continuing to drip-feed cables into the public domain despite the legal woes of its founder.
Those released on Thursday showed U.S. diplomats reporting that the illicit diamond trade in Zimbabwe had led to the murder of thousands, enriched those close to President Robert Mugabe and been financed in part by the central bank.
Any corporate groups seen as complicit in efforts to silence WikiLeaks have been attacked by online protesters. Credit card giants MasterCard and Visa came under intense cyber attack on Wednesday.
Assange's online supporters hit the corporate website of credit card firm MasterCard in apparent retaliation for its blocking of donations to the WikiLeaks website.
"We are glad to tell you that http://www.mastercard.com/ is down and it's confirmed!" said an entry on the Twitter feed of a group calling itself AnonOps.
The same group claimed responsibility for bringing down Visa Inc's site, which was temporarily unavailable in the United States, but later restored.
"Coldblood" said a battle was under way to protect the Internet.
"I see this as becoming a war, but not your conventional war. This is a war of data. We are trying to keep the Internet free and open for everyone, just the way the Internet always has been," "Coldblood" added.
Assange's main London lawyer has denied that the WikiLeaks founder ordered the attacks.
"It's very hard to get hold of anyone from WikiLeaks. The only (person) you could really get hold of was Julian, but unfortunately he's not available at the moment," said "Coldblood".
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