"While the US military was upbeat in its public outlook on the 2010 Iraqi parliamentary elections, suggesting it had helped bring stability and democracy to the country, "those of us stationed there were acutely aware of a more complicated reality," Manning wrote.

"Military and diplomatic reports coming across my desk detailed a brutal crackdown against political dissidents by the Iraqi Ministry of Interior and federal police, on behalf of Prime Minister Nuri Al-Maliki. Detainees were often tortured, or even killed."

Manning, a former US Army intelligence analyst, said he was "shocked by our military's complicity in the corruption of that election. Yet these deeply troubling details flew under the American media's radar."

Criticizing the military's practice of embedding journalists, Manning charged that "the current limits on press freedom and excessive government secrecy make it impossible for Americans to grasp fully what is happening in the wars we finance."