HAGERSTOWN, Md. — An Army officer has ordered a court martial for a low-ranking intelligence analyst charged in the biggest leak of classified information in U.S. history.

Military District of Washington commander Maj. Gen. Michael Linnington referred all charges against Pfc. Bradley Manning on Friday to a general court-martial, the Army said in a statement.

The referral means Manning will stand trial for allegedly giving more than 700,000 secret U.S. documents and classified combat video to the anti-secrecy website WikiLeaks for publication.

The 24-year-old Oklahoma native faces 22 counts, including aiding the enemy. Manning could be imprisoned for life if convicted of that charge.

A judge yet to be appointed will set the trial date.

Defence lawyers say Manning clearly was a troubled young soldier whom the Army should never have deployed to Iraq or given access to classified material while he was stationed there from late 2009 to mid-2010.

At a preliminary hearing in December, military prosecutors produced evidence that Manning downloaded and electronically transferred to WikiLeaks nearly half a million sensitive battlefield reports from Iraq and Afghanistan, hundreds of thousands of diplomatic cables, and video of a deadly 2007 Army helicopter attack that WikiLeaks shared with the world and dubbed "Collateral Murder."

Manning's lawyers countered that others had access to Manning's workplace computers. They say he was in emotional turmoil, partly because he was a gay soldier at a time when homosexuals were barred from serving openly in the U.S. armed forces. The defence also claims Manning's apparent disregard for security rules during training in the United States and his increasingly violent outbursts after deployment were red flags that should have prevented him from having been given access to classified material. Manning's lawyers also contend that the material WikiLeaks published did little or no harm to national security.

In the December hearing at Fort Meade, Maryland, prosecutors also presented excerpts of online chats found on Manning's personal computer that allegedly document collaboration between him and the WikiLeaks founder, Julian Assange.

Federal prosecutors in northern Virginia are investigating Assange and others for allegedly facilitating the disclosures.