“Major WikiLeaks announcement in Europe at 10 am tomorrow,” said the message, appearing to confirm that the site is preparing to leak what the US military and Nato fear will be tens of thousands of classified military papers compiled after the 2003 invasion of Iraq.

Their disclosure would be the most massive leak of secret documents in US history, and defense officials are racing to contain the damage.

A team of more than a hundred analysts from across the US military, lead by the Defence Intelligence Agency, has been combing through the Iraq documents they think will be released.