Wikileaks has released almost 400,000 secret US military logs, which suggest US commanders ignored evidence of torture by the Iraqi authorities.
The documents also suggest "hundreds" of civilians were killed at US military checkpoints after the invasion in 2003.
And the files show the US kept records of civilian deaths, despite previously denying it. The death toll was put at 109,000, of whom 66,081 were civilians.
The US criticised the largest leak of classified documents in its history.
A US Department of Defense spokesman dismissed the documents published by the whistleblowing website as raw observations by tactical units, which were only snapshots of tragic, mundane events.
On allegations of abuse, he said it was policy always to report "potentially illegal abusive behaviour" so action could be taken.
At a news conference in London, Wikileaks founder Julian Assange said that those snapshots of everyday events offered a glimpse at the "human scale" of the conflict.
The deaths of one or two individuals made up the "overwhelming number" of people killed in Iraq, Mr Assange said.
The new documents and new deaths contained within them showed the range and frequency of the "small, relentless tragedies of this war" added John Sloboda of Iraq Body Count, which worked with Wikileaks.
Speaking to reporters in Washington on Friday, US Secretary of State Hillary Clinton said she condemned the disclosure and suggested the leaks put lives at risk.
BBC News
