They also document cases of US military officials failing to investigate hundreds of reports of abuse, torture, rape and murder by Iraqi security forces and detail the deaths of 15,000 civilians in previously unreported incidents, the group said.
But, the largest unauthorized disclosure of classified government documents in US history confirms a long-standing assertion of former US President George W. Bush at the start of the 2007 troop surge: Iran was orchestrating one side of the Iraqi insurgency.
The documents include field reports from 2004 through 2009 describing Iranian backing for Iraqi Shiite militias and provide details supporting warnings by US officials of Iranian interference in Iraq.
Field reports released by WikiLeaks show that US military intelligence agencies had many strands of evidence revealing that Iran provided paramilitary training to Shiite insurgents at the height of the civil war in Iraq.
In one case, the military circulated a Dec. 22, 2006, warning that a group known as Jaish Al-Mahdi planned to kidnap US soldiers. The man planning the operation, Sheikh Azhar Al-Dulaimi, was trained by Hezbollah near the Iranian city of Qom, the document stated.
Analysts today generally do not dispute Iran's role in providing covert political and weapons support to insurgents in Iraq, but it was a major political issue in 2007.
Military officials clearly are not happy with the release. Nick Clegg, British deputy prime minister and leader of the Liberal Democrats, told the BBC that some of the disclosures from WikiLeaks warranted investigation.
Pentagon officials stressed that the disclosures did not reveal new information about the Iraq war and condemned the unprecedented leak of classified data.
Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, said on his Twitter account: "Another irresponsible posting of stolen classified documents by WikiLeaks puts lives at risk and gives adversaries valuable information."
WikiLeaks' last major release of documents was related to the war in Afghanistan and included the names of Afghans who helped coalition forces, potentially endangering their lives. Although the Taliban has said it was combing through the documents to find those Afghans, an assessment from the Pentagon provided to the Senate Armed Services Committee found that no one had been killed as a result of the WikiLeaks disclosure.
