FORT MEADE, MD (Reuters) - Bradley Manning, the U.S. intelligence analyst charged with leaking thousands of classified U.S. government cables to the anti-secrecy group WikiLeaks, will face a court martial on September 21, a military judge said on Wednesday.

Manning is accused of downloading more than 700,000 classified or confidential files from the military while serving in Iraq, the largest leak of classified documents in U.S. history.

Military judge Colonel Denise Lind said that military prosecutors and Manning's defense team had decided on a tentative trial schedule beginning September 21 and lasting through October 12. The trial will start more than two years after Manning was arrested.

The judge ruled against a motion filed by defense attorney David Coombs to dismiss all the charges because of what he called the prosecutor's intentional withholding of evidence needed to prepare Manning's defense.

"The court finds no evidence of prosecutorial misconduct," Lind said in a pre-trial hearing.

Manning faces 22 charges for downloading files from the military's Secret Internet Protocol Router Network, or SIPRNet, while serving in the Army's 10th Mountain Division in Iraq.

One charge, of aiding the enemy, is a capital offense. The military court has said it would not seek the death penalty, but Manning could face life imprisonment if convicted.

Other charges against Manning include wrongfully causing intelligence to be published on the Internet and theft of public property.

(Reporting By Lily Kuo; Editing by David Storey)