The self-proclaimed whistle-blower website WikiLeaks published nearly 400,000 pages of secret Defense Department documents on the Iraq war Friday evening, calling it "the largest classified military leak in history."

WikiLeaks said in a news release that the classified reports describe the Iraq war "as seen and hear by U.S. military troops" from Jan. 1, 2004 through Dec. 31, 2009.

Pentagon spokesman Geoff Morrell called document release "deplorable" and said he's concerned about "harm that could come to our forces."

According to WikiLeaks, the documents include previously undisclosed numbers of Iraqi civilian deaths, over 300 recorded reports of coalition forces committing torture and abuse of detainees, accounts of Iran meddling in the war and information suggesting there were 691 Iraqi civilians killed at U.S. military checkpoints.

It says analysis by the independent organization Iraq Body Count suggests the logs contain 15,000 civilian deaths that have not been previously disclosed publicly. The reports detail 109,032 deaths in Iraq during the six years, including 66,081 identified as civilians.

A task force of 120 analysts within the Defense Department reviewed the documents ahead of time, studying everything they thought WikiLeaks may have had access to within the "Iraq Significant Activity" reports.

The Pentagon says these reports are similar to the 70,000 Afghan war documents released by WikiLeaks this summer, but this time on a much larger scale. Similar to the last time, Morrell said, locals who worked with the U.S. military are at risk of being killed after their names are made public. He said thousands of names could be revealed, and the Pentagon has started to reach out to just over 300 Iraqis it feels are at higher risk.

WikiLeaks claims it redacted the names and got no help in doing so from the Pentagon.

Either way, Morrell said, the enemy will try to take advantage of these files.

"Remember that in the aftermath of the Afghan document leak in July, our enemies stated publicly that they were going to mine this information and look for ways that they could take advantage of it and find vulnerabilities and then exploit them," Morrell said in an interview with Fox late Friday. "Our intelligence backs that up. This leak is potentially four times as large as the last one."

The documents also shed new light on Iran's role aiding militias and allegations of detainee abuse by Iraqi security forces, reportedly without objection from the U.S.

NATO chief Anders Fogh Rasmussen described such a document release as "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 earlier Friday in Berlin following a meeting with German Chancellor Angela Merkel.

Wikileaks' previous release in July of secret war documents from Iraq and Afghanistan outraged the Pentagon, which accused the group of being irresponsible. Fogh Rasmussen said Friday that leaks of this nature "may put soldiers as well as civilians at risk."

It appears that those fears -- which the military has invoked in its appeal to WikiLeaks and the media not to publish the documents -- have yet to materialize. A Pentagon letter obtained by The Associated Press reported that no U.S. intelligence sources or practices were compromised by the Afghan war logs' disclosure.

Still, the military feels any classified documents release can harm national security and raise fears for people who might consider cooperating with the U.S. in the future, Lapan said.

Ryan Crocker, U.S. ambassador to Iraq from 2007-08, said the disclosures would be more worrisome if the U.S. were still fully engaged in combat in Iraq -- but he still sees it as a major problem.

"I'd really be worried if -- as looks to be the case -- you have Iraqi political figures named in a context or a connection that can make them politically and physically vulnerable to their adversaries," he told a conference Friday at the Center for Strategic and International Studies in Washington.

"That has an utterly chilling effect on the willingness of political figures to talk to us -- not just in Iraq but anywhere in the world," he said.

The Associated Press contributed to this report.