Lawyers for the five accused 9/11 plotters urged President Barack Obama Friday to declassify a detention and interrogation program used in secret CIA prisons where their clients were allegedly tortured.
Navy commander Walter Ruiz, who represents Saudi suspect Mustapha al-Hawsawi, asks in the joint letter with other defense attorneys for access to details, invoking international law.
"Today uniformed officers and our civilian colleagues join in asking our president to uphold our obligations under the (United Nations) Convention Against Torture and remove improper classification restrictions, which are preventing the pursuit of truth and meaningful justice," Ruiz wrote in a statement accompanying the letter to the White House.
Following their detentions, in 2002 and 2003, the five suspects spent three years in secret Central Intelligence Agency prisons abroad where they were subjected to harsh interrogation techniques like simulated drowning,or waterboarding, which many consider a form of torture.
US authorities have, for example, admitted that the self-proclaimed mastermind of the attacks, Khalid Sheikh Mohammed, was subjected to 183 instances of waterboarding.
During pre-trial hearings this week at the high security US facility in Cuba, where the detainees have been held since 2006, the lawyers also invoked the UN Convention Against Torture to urge that the death penalty be eliminated as a possible sentence for their clients.
Detainees could not file complaints under the convention, their lawyers said, because their treatment in US detention was a classified matter.
"Evidence of war crimes must not be classified," Ruiz said.
"For decades now, the United States, by executive order has banned the use of classification rules to conceal violations of law."
The Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment was adopted by the UN General Assembly in 1984.
Signed by the United States in 1988 and ratified by the Senate in 1994, it "is part of United States law," he added.
The attacks on New York and Washington on September 11, 2001, killed nearly 3,000 people.