It said that the major findings included a US military cover-up of Iraqi state-sanctioned torture and "hundreds" of civilians deaths at manned American checkpoints after the US-led invasion of 2003 that ousted Saddam Hussein.
The Qatar-based satellite broadcaster also said the leaked papers, dating from January 1, 2004 to December 31, 2009, show the United States kept a death count throughout the war, despite US denials.
Al-Jazeera's English channel was to broadcast a series of programmes from 2100 GMT on Friday, it said in a statement sent to AFP, "that reveal startling new information about the operations of US forces during Iraq War."
"The secrets documents are more than four times larger then WikiLeak's Afghanistan files," the broadcaster said in a statement issued in English.
