In a military hearing at Fort Meade, Md., Army Pfc. Bradley E. Manning pleaded guilty to charges he illegally got and gave to WikiLeaks highly classified U.S. government secrets and agreed to serve 20 years in prison, the Los Angeles Times reported.
Manning, however, pleaded not guilty to 12 more serious charges, including espionage for aiding the enemy, meaning his criminal case will proceed at a general court-martial in June.
WikiLeaks, a whistle-blowing website, has published millions of pages of classified U.S. military and diplomatic documents and communications.
During Thursday's hearing, Manning admitted he leaked a video of a helicopter gun battle, State Department cables, an Army field manual and Army documents about the military's patrol reports in Afghanistan and Iraq.
He also admitted leaking confidential assessments of detainees at the U.S. prison in Guantanamo Bay, Cuba, and classified records from a U.S. bombing in Afghanistan's Farah province in which as many as 30 civilians were killed.
Army Col. Denise Lind asked Manning frequently if he wanted enter the guilty pleas, the Times said. Each time, Manning answered, "Yes, ma'am," and "Yes, your honor."
Manning has been in a military prison since his arrest in May 2010.
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