Whistle-blowing website WikiLeaks has released nearly 400,000 secret American documents on Iraq war, calling it the "largest classified military leak in history", despite Pentagon's warning that it could endanger informants and reveal war strategy.

The latest leaked documents chronicling the Iraq war from 2004 through 2009 provide a new picture of how many Iraqi civilians were killed, open a new window on the role that Iran played in supporting Iraqi militants and give many accounts of abuse by the Iraqi Army and police, said the New York Times, one of the newspapers which got early access to the papers.

WikiLeaks called the document drop “the largest classified military leak in history”. In a news release, the group said the documents detail 109,032 deaths in Iraq, encompassing 66,081 civilians, 23,984 insurgents, 15,196 Iraqi government forces and 3,771 coalition forces, according to the classifications used by the US military.

Hours ahead of the anticipated release of the documents, State Department spokesman P.J. Crowley said the US condemns the fact that WikiLeaks will continue to release this classified information.

"We do believe it continues to put both our personnel and our interests at risk. We wish heartily that they wouldn't do it, and we wish heartily that news media organisations wouldn't cooperate with them," he said.

Refraining from making any comment, secretary of state Hillary Clinton told reporters: "I do have a strong opinion that we should condemn in the most clear terms the disclosure of any classified information by individuals and organisations which puts the lives of United States and partner service members and civilians at risk, threatening our national security and the national security of those with whom we are working."

The Pentagon also strongly condemned the unauthorised disclosure of classified information contained in 392,000 documents as a danger to national security. "...'significant activities' reports (in the leaked documents) are initial, raw observations by tactical units," Pentagon press secretary Geoff Morrell told reporters.

"They are essentially snapshots of events, both tragic and mundane, and do not tell the whole story. That said, the period covered by these reports has been well-chronicled in news stories, books and films and the release of these field reports does not bring new understanding to Iraq's past," Morrell said.

The Pentagon had established a task force that had been combing through the Iraq data base to assess the damage that a Wikileaks publication of nearly 400,000 significant activity reports could pose to the US military, Iraqi allies and ongoing operations.

Morrell said the US Central Command is reaching out to more than 300 Iraqis it feels are at significant risk for reprisal after their names were exposed within documents.
He said thousands of names were exposed, yet these 300 or more are at higher risk.

According to the New York Times, hundreds of reports of beatings, burnings and lashings suggested that "such treatment was not an exception."

Most abuse cases contained in the new batch of leaks appear to have been ultimately ignored, the daily said, adding that military rules require forces to report abuse to Iraqi authorities, but suggested that there was little follow-up on abuse reports.

WikiLeaks editor-in-chief Julian Assange told CNN that the new round of field reports shows "compelling evidence of war crimes" committed by forces of the US-led coalition and the Iraqi government.

After studying the documents, the NYT said Iran's military, "more than has been generally understood, intervened aggressively in support of Shia combatants, offering weapons, training and sanctuary and in a few instances directly engaging American troops."

"The death of civilians at the hands mainly of other Iraqis, but also of the American military — appear to be greater than the numbers made public by the United States during the Bush administration," it added.

Earlier in 2010, WikiLeaks had made available in advance 92,000 Afghanistan-related documents to the NYT, Britain's Guardian and Germany's Der Speigel.

The information supported existing suspicions like Pakistan's ISI links with extremists and extra-judicial killings by US forces. This time, the Iraqi documents were made available to the New York Times, The Guardian, Le Monde, Al Jazeera, and Der Spiegel.

The NYT, separately, quoted Morrell as saying that "We deplore WikiLeaks for inducing individuals to break the law, leak classified documents and then cavalierly share that secret information with the world, including our enemies."

"We know terrorist organisations have been mining the leaked Afghan documents for information to use against us and this Iraq leak is more than four times as large. By disclosing such sensitive information WikiLeaks continues to put at risk the lives of our troops, their coalition partners and those Iraqis and Afghans working with us."

The documents, according to the newspaper, showed the December 2006 was the worst month for civilian deaths with about 3,800 fatalities. They also revealed that during the Shia-Sunni civil war the military sided with Shia militias and in some instances also fought with US forces. The documents said that in several instances Iraqi civilians were shot from US helicopters.