Whistle-blowing website WikiLeaks is under a sustained distributed denial of service (DDoS) attack that has taken it offline for almost a week.

The attack began during the middle of last week (August 8) and the site remained offline at the time of going to press.

A group calling itself AntiLeaks has popped up on Twitter claiming responsibility for the attack. A message posted on its Twitter feed, which was only activated in early August, suggested Julian Assange’s current issues with the law are at least partly behind the attack. "Don’t give asylum to a coward like Julian Assange. He deserves to be held accountable for his crimes," the tweet read.

A more detailed statement from the group said it wanted to halt Assange’s bid for asylum in Ecuador. AntiLeaks described him as a "new breed of terrorist."

Taking to its own Twitter feed WikiLeaks said: "The attack is well over 10Gbits/second sustained on the main WikiLeaks domains. The bandwidth is used is so huge it is impossible to filter without specialized hardware, however the DDoS is not simple bulk UDP or ICMP packet flooding, so most hardware filters won’t work either."

"The rage of IPs used is huge. Whoever is running it controls thousands of machines or is able to simulate them," the statements added.

The attacks also targeted its donations infrastructure, WikiLeaks said. However the site managed to set up alternative sites, meaning it could continue to receive donations.

However, the site also criticised the US government, suggesting WikiLeaks believes it could be behind the current attacks.

"By attacking us all the U.S. does is make our networks stronger, present in more countries and with a higher degree of popular support. Or, the U.S. can choose not to attack us, in which case we have more resources to allocate to publications and research. Either way, we win," the tweets said.

The attacks come as WikiLeaks publishes more emails it acquired after the Stratfor hack, which was claimed to have been carried out by hacktivism group Anonymous. The original release of files contained information about Stratfor, such as its "web of informers, pay-off structure, payment-laundering techniques and psychological methods," WikiLeaks said at the time.

The latest batch of documents concern something called TrapWire, which is a surveillance system developed by US firm Abraxis. However documents leaked by WikiLeaks claim the systems is being used by the US government to spy on its own citizens.

It is claimed the TrapWire system can gather CCTV images of anyone considered to be acting suspiciously. The government can then use facial recognition software and other analysis tools to identify people.

According to the hacked Stratfor emails the system is also being used by the UK government. According to Stratfor president Don Kuykendall, "clients include Scotland Yard, #10 Downing [Street] the White House and many [more]."

Google and salesforce.com were also listed as potential customers of TrapWire, the emails revealed.