Lawyers for WikiLeaks suspect Bradley Manning asked a military court Wednesday to throw out 10 of 22 counts filed against the US Army private for allegedly leaking documents to the site.

Manning, 24, is accused of leaking hundreds of thousands of military logs from Iraq and Afghanistan -- as well as US diplomatic cables on a wide range of issues -- to whistleblower WikiLeaks while serving as a low-ranking intelligence analyst.

He could be jailed for life if convicted of "aiding the enemy," one of 22 criminal charges that judge Colonel Denise Lind let stand at pre-trial hearings in April at Fort Meade, a military base in Maryland outside Washington.

Defense lawyers have however said in motions filed with the court that the US government used "unconstitutionally vague" or "substantially overbroad" language in eight of those counts, in which Manning is accused of "possession and disclosure of sensitive information."

For two other counts, in which Manning is accused of "having knowingly exceeded authorized access" to a secret Defense Department computer network, his attorneys said the government failed to state an offense.

The baby-faced Manning, who was formally charged in February and looked frail Wednesday, faces trial on September 21. He has yet to enter a plea in the case. Later this month, the court is scheduled to discuss a list of witnesses.

WikiLeaks, an anti-secrecy site created by Julian Assange, caused a diplomatic firestorm when it published documents Manning allegedly sent its way between November 2009 and May 2010.

Manning is painted as a traitor by some for his alleged role in the worst ever breach of US intelligence, which embarrassed Washington and dismayed US allies.

But his supporters view Manning as a political prisoner and praise WikiLeaks for uncovering government secrets.

David Coombs, a member of Manning's defense team, told the court US government agencies were dragging their feet in providing documents his team had requested to build their case.

The 28 that had so far been made available suggested there was minimal fallout from Manning's alleged leaks, he added.

"They have an obligation," Coombs said. "At this point we received less than half of the 63 documents ... and they basically say there's no damage, no impact."

To give the agencies time to compile the missing material, Coombs called on Lind to briefly postpone the proceedings.

"If the government has nothing to hide... we're asking to suspend the hearing for two to three weeks," he said.

The hearing that opened Wednesday is set to run for three days.