A group of "hacktivists" who crippled websites in revenge for cutting off services to whistle-blowing website WikiLeaks have warned they will continue their "digital sit-in" in a campaign for total internet freedom.
The loose-knit group, known as Anonymous, has disrupted sites belonging to finance giants including MasterCard and Visa by bombarding their websites with millions of bogus visits during a campaign called "Operation Payback".
Their blog post vowing to fight any organisation which supports censorship came as WikiLeaks' payment processor, DataCell, said it was preparing to take legal action against the credit card companies over their refusal to process donations.
DataCell chief executive Andreas Fink said: "It is obvious that Visa is under political pressure to close us down. We strongly believe a world-class company such as Visa should not get involved in politics and just simply do their business where they are good (at it). Transferring money."
In a blog linked to its Twitter account, Anonymous wrote: "Hello World. We are Anonymous. What you do or do not know about us is irrelevant. We have decided to write to you, the media, and all citizens of the free world at large to inform you of the message, our intentions, potential targets, and our ongoing peaceful campaign for freedom.
"The message is simple - freedom of speech. Anonymous is peacefully campaigning for freedom of speech everywhere in all forms. Freedom of speech for: the internet, for journalism and journalists, and citizens of the world at large. Regardless of what you think or have to say; Anonymous is campaigning for you."
The post continued: "The internet is the last bastion of freedom in this evolving technical world. The internet is capable of connecting us all. When we are connected we are strong. When we are strong we have power. When we have power we are able to do the impossible. This is why the government is moving on WikiLeaks. This is what they fear. They fear our power when we unite. Do not forget this."
Anonymous launched a series of so-called distributed denial-of-service (DDoS) attacks against various websites including the credit card companies, PayPal, and the Swedish prosecutor's office, which is acting in the legal case against WikiLeaks founder Julian Assange.
Assange is on remand in London after being arrested and refused bail over sexual offence charges he is facing in Sweden.
DDoS attacks, which are illegal in the UK, involve overloading a website with high numbers of requests so it stops working. Anonymous said it was leading a "peaceful campaign" and denied being a terrorist or vigilante organisation.