Khalid Sheikh Mohammed, the alleged mastermind of the September 11 attacks, is pictured before judge Colonel James Pohl (R) wearing a military-style camouflage vest on the third day of pre-trial hearings in the 9/11 war crimes prosecution as depicted in this Pentagon-approved courtroom sketch at the U.S. Naval Base Guantanamo Bay, Cuba, October 17, 2012. REUTERS/Janet Hamlin

Guantanamo Bay Naval Base, Cuba - The alleged mastermind of the September 11 attacks showed up in the Guantanamo war crimes courtroom on Wednesday wearing a military-style camouflage vest over his white tunic, suggesting he may try to invoke protections reserved for soldiers.

A U.S. Army judge ruled on Tuesday that Khalid Sheikh Mohammed and four co-defendants charged with plotting the 2001 hijacked plane attacks could wear what they want to court, so long as it did not pose a security risk or include part of a U.S. military uniform like those worn by their guards.

The ruling came during a week of pretrial hearings in the September 11 case at the Guantanamo Bay U.S. Naval Base in Cuba.

The rationale for Mohammed's wardrobe choice was unclear. His lawyers had argued that he should be allowed to wear a woodland-patterned camouflage vest to court because he wore one as part of a U.S.-armed mujahideen force fighting against Russian troops that occupied Afghanistan in the 1980s.

“Mr. Mohammed has previously distinguished himself on the battlefield by wearing a military-style vest or clothing. He did it in Afghanistan for the U.S. government during that proxy war, he did it in Bosnia and he has a right to do it in this courtroom,” his defense attorney, Army Captain Jason Wright, said on Tuesday.

The United States is trying Mohammed and the other alleged al Qaeda conspirators as unlawful belligerents who are not entitled to the combat immunity granted to soldiers who kill in battle.

They are accused of recruiting, funding and training the hijackers who slammed commercial jetliners into buildings in the United States in 2001, killing 2,976 people. The defendants could face the death penalty if convicted of charges that include conspiring with al Qaeda, attacking civilians and civilian targets, murder in violation of the laws of war, destruction of property, hijacking and terrorism.

Under the Geneva Conventions, one of the things that separate soldiers from unlawful belligerents is the wearing of uniforms that distinguish them from civilians. Soldiers must also follow a clear command structure, carry arms openly and adhere to the laws of war.

Wright had argued that forbidding Mohammed from wearing military-style garb could undermine his presumption of innocence in the war crimes tribunal.

“The government has a burden to prove that this enemy prisoner of war is an unprivileged enemy belligerent,” Wright argued. - Reuters