“WikiLeaks.org is presently under attack,” the anti-secrecy group said on Twitter. An hour later, the site and the cables posted there were inaccessible.
WikiLeaks later updated its Twitter account to say it was “still under a cyber attack” and directed followers to search for cables on a mirror site or a separate search system, cablegatesearch.net.
The apparent cyber attack yesterday comes after current and former American officials said the recently-released cables were creating a fresh source of diplomatic setbacks and embarrassment for the Obama administration.
The releases have also provoked outrage from elsewhere, with Australia’s Attorney General Robert McClelland criticising the release of a US cable naming 23 people with alleged links to al-Qaida.
“On occasions in the past, WikiLeaks has decided to redact identifying features where security operations or safety could be put at risk. This has not occurred in this case,” he said. “The publication of any information that could compromise Australia’s national security – or inhibit the ability of intelligence agencies to monitor potential threats – is incredibly irresponsible.”
A review more than 2,000 of the cables recently released by WikiLeaks contained the identities of more than 90 sources who had sought protection and whose names the cable authors had asked to protect.
Officials said the disclosure in the past week of more than 125,000 sensitive documents by WikiLeaks endangered informants and jeopardised US foreign policy.
The officials would not comment on the authenticity of the leaked documents but said the rate and method of the new releases, including about 50,000 in one day alone, presented new complications.
Some of those deemed to be at risk following the latest disclosures in unredacted documents have since been located and moved.
The first series of leaks, which began in November and sent the administration into a damage-control frenzy.
WikiLeaks hit back at the criticism even as its website came under cyber attack. “Dear governments, if you don’t want your filth exposed, then stop acting like pigs. Simple,” the group posted on Twitter.
Some officials noted the first releases had been vetted by media organisations which scrubbed them to remove the names of contacts that could be endangered. The latest documents have not been vetted in the same way.
“It’s picking at an existing wound. There is the potential for further injury,” said PJ Crowley, the former assistant secretary of state for public affairs who resigned this year after criticising the military’s treatment of the man suspected of leaking the cables to WikiLeaks.
WikiLeaks insisted it was “totally false” that any WikiLeaks sources had been exposed and appeared to suggest the group itself was not even responsible for releasing unredacted cables.
The group seemed to taunt US officials and detractors in yet another Twitter message, asking what they would do “when it is revealed which mainstream news organisation disclosed all 251k unredacted cables”.
The accelerated flood of publishing partly reflects the collapse of the unusual relationships between WikiLeaks and news organisations that previously were co-operating with it in exchange for being given copies of all the uncensored State Department messages.