The US struck its first blow against WikiLeaks after Amazon.com pulled the plug on hosting the whistleblowing website in reaction to heavy political pressure.

The company announced it was cutting WikiLeaks off yesterday only 24 hours after being contacted by the staff of Joe Lieberman, chairman of the Senate's committee on homeland security.

WikiLeaks expressed disappointment with Amazon, and insisted it was a breach of freedom of speech as enshrined in the US constitution's first amendment. The organisation, in a message sent via Twitter, said if Amazon was "so uncomfortable with the first amendment, they should get out of the business of selling books."