The inspector general charged with overseeing the department of defence has ordered the US Southern Command, which runs the prison camp, to examine the accusations, Gary Comerford, the command spokesman, said on Friday.
"On the afternoon of October 10, a complaint was received. On the 12th, we forwarded it to Southcom for action, and that action is to take a look into it," Comerford said.
Local media reported last week that a woman, apparently from the Marine Corps, said in an affidavit that Guantanamo guards had admitted to having committed physical and psychological abuse of prisoners, including beating the head of one inmate against a door and randomly denying rewards to others just to make them angry.
"The hot line complaint did consist of the letter from the [Marine's] attorney and the affidavit. However, there is really nothing that we can say about the letter and its content."
The Pentagon inspector general receives about 14,000 complaints annually from members of the armed forces on the hot line, he said. The military looks into about 3,000 of these.
Robert Durant, a spokesman at the Guantanamo camp, said on Friday that the camp has been informed of the investigation and that the joint task force running the camp "will cooperate fully with Southcom to learn the facts of the matter and will take action where misconduct is discovered".
"On the afternoon of October 10, a complaint was received. On the 12th, we forwarded it to Southcom for action, and that action is to take a look into it"
"The mission of the Joint Task Force is the safe and humane care and custody of detained enemy combatants. Abuse or harassment of detainees in any form is not condoned or tolerated," he said.
About 450 inmates are currently at the camp, most held as "enemy combatants" without charge or access to a lawyer.
Since the camp opened in January 2002, the US military has detained and interrogated 750 prisoners there. Most were captured after the US-led war in Afghanistan against the Taliban government following the September 11, 2001, attacks in the United States.