In a message posted to its Twitter page on Thursday, the organization said there was a "major WikiLeaks press conference in Europe coming up." WikiLeaks has not commented publicly on the imminent announcement.
Their disclosure would be the most massive leak of secret documents in U.S. history, and defense officials are racing to contain the damage.
A team of more than a hundred analysts from across the U.S. military, lead by the Defense Intelligence Agency, has been combing through the Iraq documents they think will be released.
Called the Information Review Task Force, its analysts have pored over the documents and used word searches to try to pull out names and other issues that would be particularly sensitive, officials have said.
The task force has informed the U.S. Central Command of some of the names of Iraqis and allies and of other information they believe might be released that could present a danger, officials have said, noting that - unlike the WikiLeaks previous disclosure of some 77,000 documents from Afghanistan - in this case they had advance notice that names may be exposed.
That previous leak, back in July, outraged the U.S. military, which accused WikiLeaks of irresponsibility.
But The Associated Press has obtained a Pentagon letter reporting that no U.S. intelligence sources or practices were compromised by the posting of secret Afghan war logs.
Although U.S. officials still think the leaks could cause significant damage to U.S. security interests, the assessment suggests that some of the administration's worst fears about the July disclosure have so far failed to materialize.
Defense Secretary Robert Gates reported the conclusions in an Aug. 16 letter to Sen. Carl Levin, chairman of the Senate Armed Services Committee, who had requested a Pentagon assessment.