The Iraqi Foreign Minister has criticised the release of confidential US diplomatic cables as "very, very unhelpful".
WikiLeaks has started to release a quarter of a million confidential documents detailing embarrassing and inflammatory episodes.
It has been shown that Arab rulers secretly lobbied America to launch air strikes to destroy Iran's nuclear programme.
The online whistleblower said today unknown hackers trying to prevent the release of hundreds of thousands of classified US State Department documents caused the site to crash.
WikiLeaks said on Twitter yesterday that its website was “under a mass distributed denial of service attack” but promised that Spain’s El Pais, France’s Le Monde, Germany’s Der Spiegel, Britain’s Guardian newspaper and The New York Times “will publish many US embassy cables tonight, even if WikiLeaks goes down”.
WikiLeaks had given the media outlets early access to the diplomatic cables to publish in conjunction with their release on its site.
WikiLeaks’ website was inaccessible for much of yesterday, though several hundred cables were posted on its site by late afternoon. The cables, many of them classified, offer candid, sometimes unflattering assessments of foreign leaders, ranging from US allies such as Germany and Italy to other nations like Libya, Iran and Afghanistan.
In a typical denial-of-service attack, remote computers commandeered by rogue programmes bombard a website with so many data packets that it becomes overwhelmed and unavailable to visitors.
Pinpointing the culprits was impossible because the internet’s structure does not allow for the tracing back of the data packets used in such attacks, computer security expert Bruce Schneier said.
Hackers have used denial-of-service attacks over the years to target corporate and government websites.
Last month political bloggers in Vietnam said they were victimised by cyberattacks designed to block their websites to stifle government dissent. Other targets have included US and South Korean government websites in 2009 and computer networks in Estonia, which were crippled for nearly three weeks in 2007 by what were believed to be Russian hackers.
In the weeks leading up to the 2008 war between Russia and Georgia, Georgian government and corporate websites were hit with denial-of-service attacks. The Kremlin denied involvement.
James Lewis, a cybersecurity expert and a senior fellow at the Centre for Strategic and International Studies, said it was unlikely the US or some other government would use denial-of-service attacks against WikiLeaks.
His best guess was “a bunch of geeks who’ve decided they’re annoyed with WikiLeaks”.
“Denial of service is usually the amateur’s approach,” he said. “Usually it’s the hacker community.”
Mr Lewis said he had never heard of the US trying to attack a website like this.
“Usually they’re more interested in exploiting, that is getting into WikiLeaks to figure out what’s going on. Or they’re interested in doing some kind of damage, and denial of service really doesn’t do any damage,” he said.
Such an attack would only stall WikiLeaks, not prevent the information from being released.
Mr Schneier also said he seriously doubted any US government agency would be involved in such an attack because it amounted to a mere “nuisance” and could not stop Wikileaks from releasing the diplomatic cables. He notes that there were many ways to distribute information online.
An encrypted file that was made available online using BitTorrent file-sharing technology in late July is believed to hold the cables. All Wikileaks would need to do to unlock the file is distribute the key.