FORT MEADE, Md. - A military judge refused on Wednesday to throw out the charges against a U.S. Army private accused of providing thousands of sensitive documents to Wikileaks in the biggest leak of government secrets in the country's history.

Army Col. Denise Lind denied the defence motion to dismiss all 22 charges during a pretrial hearing in the court-martial of Pfc. Bradley Manning.

Manning is accused of sending hundreds of thousands of sensitive documents to Wikileaks, the anti-secrecy website run by Julian Assange. The U.S. government says the publication of that material online aided al-Qaida in the Arabian Peninsula.

The defence has filed several motions seeking dismissal of individual charges, including the most serious, aiding the enemy. That offence carries a maximum penalty of life imprisonment.

Lind scheduled the trial to run from Sept. 21 through Oct. 12. She also scheduled four more hearings in June, July, August and September.

Manning hasn't entered a plea. He also hasn't yet decided whether he will be tried by a judge or a jury.

Lind also ruled that prosecutors don't have to provide the defence with transcripts of federal grand jury testimony regarding government secrets disclosed by Wikileaks.

Lind said that while the FBI and the Army have jointly pursued a WikiLeaks investigation, military prosecutors have no authority to release FBI documents.

On Tuesday, the two sides engaged in a sometimes heated courtroom debate over defence claims that prosecutors haven't met their obligation to provide Manning's lawyers with evidence they uncover that could aid the defence, a process called discovery.

Manning's lawyers had argued that prosecutors were so slow in sharing required information with the defence that the only remedy was to throw out the charges.

Prosecutors maintained that they needed time to obtain documents from civilian agencies and search the records for relevant material. They also accused the defence of making an overly broad, vague request for information.

The 24-year-old Manning was ordered court-martialed after he was accused of downloading the documents, diplomatic cables and video clips, then sending them to WikiLeaks. He was working as an intelligence analyst in Baghdad when authorities say he copied classified material from government computers in late 2009 and early 2010.

The material WikiLeaks published included cockpit video of a 2007 U.S. Apache helicopter attack that killed a number of civilians, including a Reuters news photographer and his driver. The U.S. government says the civilian deaths were accidental.

Manning has been in pretrial confinement since he was charged in May 2010. His treatment at a Marine Corps base, where he was confined 23 hours a day in a single-bed cell, caused support for him to swell both in the U.S. and overseas.

The Quantico, Virginia, brig commander cited safety and security concerns. For several days in March 2011, Manning was forced to sleep naked, purportedly for injury prevention, before he was issued a suicide-prevention smock.

Manning's supporters have raised funds to place posters in the Washington Metro subway system this week portraying him as a whistleblower, patriot and hero.