Such treatment violated the military's own regulations and could result in charges being dropped against Manning, The Guardian reported.
David Coombs, Manning's civilian attorney, accused the military of forcing harsh conditions on his client during detention following his 2010 arrest. Coombs made the charges in an Article 13 filing he posted Friday on his Web site.
Among the charges, Coombs said Manning was punished through "degradation and humiliation" by forcing him to stand naked outside his cell during a morning inspection, an action the attorney claimed was "retaliatory punishment" for Manning complaining about his treatment.
Manning was kept in a 6-foot by 8-foot cell for 23 to 24 hours a day, the attorney says, and was ordered not to lie down, unless he was sleeping, or use a wall to support himself..
Article 13 of the Uniform Code of Military Justice says no one awaiting trial may be given punishment "any more rigorous than the circumstances required to insure his presence."
If a judge finds Manning has been subjected to illegal treatment, the soldier could get credit for time served in detention or even have the charges dropped.
A 14-month investigation by the United Nations special rapporteur on torture concluded Manning had been subjected to cruel and inhuman conditions.