GUANTANAMO BAY, Cuba -- A defence lawyer who gained rare access to an ultra-secret section of the Guantanamo Bay prison said Sunday that the camp does not meet international standards under the Geneva Conventions, an allegation denied by the chief prosecutor for the U.S. military's war crimes tribunal.

James Connell, a lawyer for one of the five Guantanamo prisoners charged in the Sept. 11 terror attack, plans to file a motion with the judge presiding over the tribunal challenging the conditions in the section known as Camp 7.

Connell won approval from the judge to spend 12 hours with two experts inside Camp 7, which holds men deemed "high-value detainees" by the U.S. military and is so shrouded in secrecy that its location on the U.S. base in Cuba is classified. The lawyer said he was prevented from seeing how to get to Camp 7 and is not permitted to reveal exactly what he saw, but he said it amounts to pretrial punishment, which is prohibited under military regulations.

"The conditions of confinement do not meet the standards for preventative detention under the laws of war," Connell said.

Brig. Gen. Mark Martins, the chief prosecutor, denied that Camp 7 fails to meet international standards. He said the security is designed to prevent the release of classified information by high-value detainees, who include all five men charged in the Sept. 11 attack.

"We take very seriously humane standards," he said.

Camp 7 opened in 2006 to hold prisoners who were held in CIA prisons overseas and subjected to the harsh interrogations that critics say amounted to torture. The prisoners held there do not live in communal pods like most of the prisoners held at Guantanamo and they cannot make phone calls to their families.

Lawyers for the other defendants in the Sept. 11 case are also expected to tour Camp 7 and will likely file similar challenges.

Connell's comments came before the start on Monday of a weeklong pretrial hearing in the Sept. 11 case to deal with procedural issues that must be resolved before a trial that is at least a year away.