The WikiLeaks website is poised to release what the Pentagon fears is the largest cache of secret U.S. documents in history - hundreds of thousands of intelligence reports that could amount to a classified history of the war in Iraq.
U.S. officials condemned the move and said Friday they were racing to contain the damage from the imminent release, while NATO's top official told reporters he feared that lives could be put at risk by the mammoth disclosure.
NATO chief Anders Fogh Rasmussen said any release would create "a very unfortunate situation."
"I can't comment on the details of the exact impact on security, but in general I can tell you that such leaks ... may have a very negative security impact for people involved," he told reporters Friday in Berlin following a meeting with German Chancellor Angela Merkel.
In a posting to Twitter, the secret-spilling website said there would be a "major WikiLeaks announcement in Europe" at 0900 GMT (5 a.m. EDT) Saturday. The group has revealed almost nothing publicly about the nature of the announcement.