WikiLeaks suspect Bradley Manning appeared at a military court outside Washington Wednesday for a pretrial hearing at which his lawyers were seeking dismissal of 10 of the 22 counts against him.

A frail-looking Manning was seated between two members of his defense team as the hearing got underway after an hour-long closed door hearing between lawyers for both sides.

The defense are set to argue their case at a three-day hearing at the military tribune where Manning, 24, is on trial for allegedly leaking hundreds of thousands of military logs from Iraq and Afghanistan and US diplomatic cables to WikiLeaks while serving as a low-ranking intelligence analyst in Iraq.

In motions filed ahead of the hearing, defense lawyers said the US government used "unconstitutionally vague" or "substantially overbroad" language in eight counts of their indictment, 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, defense lawyers said the government failed to state an offense.

Manning, who was formally charged in February, faces a September 21 trial for "aiding the enemy" -- a charge that carries a potential life sentence -- in addition to numerous other counts.

He is being tried at a Fort Meade military base in Maryland, a short distance from the US capital.

[US Army Private Bradley Manning (2nd R) is escorted during his arrival to military court on the first day of a three-day motion hearing in Fort Meade, Maryland. AFP Photo/Alex Wong]