The executive order was one of three expected imminently on how to interrogate and prosecute al-Qaida, Taliban or other foreign fighters believed to threaten the United States.
A senior Obama aide said the president would sign the order on Thursday, fulfilling his campaign promise to shut down a facility that critics around the world say violates domestic and international detainee rights. The aide spoke on condition of anonymity because the event has not yet been announced.
The Associated Press obtained a copy of the draft earlier Wednesday.
Closing the facility in Cuba "would further the national security and foreign policy interests of the United States and the interests of justice," read a draft prepared for the new president's signature.
While some of the detainees currently held at Guantanamo would be released, others would be transferred elsewhere and later put on trial under terms to be determined.
It was not known when Obama intended to issue the order. He has been a longtime critic of the Bush administration's decision to maintain the detention facility, which was opened after the Sept. 11, 2001, terrorist attacks.
There are an estimated 245 detainees currently held at Guantanamo, out of some 800 who were sent there during the Bush administration.
The order circulated as the judge in one war crimes case agreed to Obama's request to suspend proceedings pending a 120-day review.
Army Col. Stephen Henley issued the ruling Wednesday after a brief hearing at the U.S. base in Cuba.
The defendants opposed the delay. All have said they want to plead guilty to charges that carry a potential death sentence.
It was not immediately clear whether the request to halt proceedings was designed as a precursor to a more extensive executive order.
The draft order calls for a systematic review of the cases of each of the detainees, to determine which among them can be released and which cannot.
"It is in the interests of the United States to review whether and how such individuals can and should be prosecuted," it says.
The facility at Guantanamo Bay has long been criticized by critics of the former Bush administration at home, as well as by other governments overseas, as a black eye for the United States. The administration established it early in the war on terror, contending that those held there were not entitled to the customary rights that prisoners in he United States enjoy, or to the protections of the Geneva Conventions that cover war prisoners.
The draft order notes that some of those held at the site have been there for more than six years, and most for at least four years.
The draft states that "the detention facilities at Guantanamo for individuals covered by this order shall be closed as soon as practicable, and no later than one year from the date of this order."
At the Pentagon, military leaders were preparing for the order that spokesman Bryan Whitman said would begin a "comprehensive review of policies and procedures related to detainee activities."
"The president has clearly made his intentions well known," Whitman said. "And he has taken the first steps with respect to his direction to order a pause to military commission proceedings."
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