A court and execution chamber could be built at the US detention camp in Cuba under plans being drawn up by military officials.
Some detainees may be executed if convicted at military trials
Military tribunals for some of the hundreds of men detained at the US base on Guantanamo Bay moved a step closer last month with the appointment of a chief prosecutor and chief defence counsel.
Pentagon rules for the tribunals permit death sentences to be passed and the construction of a death chamber at the camp is among options being considered.
But defence officials stress that everything remains on the drawing board until orders are issued by the president.
"We have a number of plans that we work for short-term and long-term strategies but that's all they are - plans," camp commander Major-General Geoffrey Miller told the Associated Press news agency.
Renovation work such as rewiring has begun on a number of buildings which could later be designated as courts for the tribunals.
General Miller told AP there are also plans to build a permanent prison block for those convicted and sentenced and an execution chamber should any be sentenced to death.
"We're getting ready so we won't be starting from scratch," he said.
The detainees held at Camp Delta on the isolated US base include about 680 people captured during the war against the Taleban in Afghanistan, launched by the US after the 11 September 2001 attacks.
All have been classified as "enemy combatants" and as such are not entitled to legal representation or a civil trial.
None have yet been charged though cases are being prepared against 10 or more detainees.
After the detention centre opened in January 2002, US Defence Secretary Donald Rumsfeld called its inmates "among the most dangerous, best trained, vicious killers on the face of the Earth".
Makeshift camp conditions attracted criticism
But many are now thought to be low-level fighters.
Human rights groups have criticised both the makeshift conditions at the prison camp and the lack of rights afforded to the detainees.