Tariq Ba Odah has not been eating voluntarily since 2007.
Lawyers from the US justice department have blocked a legal request, made on health grounds, to release a Guantanamo Bay detainee who weighs just 34kg after an eight-year hunger strike.
Yemeni detainee Tariq Ba Odah, 36, has been force-fed by nasal tube since he stopped eating solid food in 2007.
His weight loss over the last 18 months has raised fears among his lawyers that he could die of starvation. Pentagon officials said he was receiving proper care.
US intelligence and military officials cleared Ba Odah for release six years ago from the Guantanamo detention centre, where 116 men are imprisoned on a US navy base in Cuba, 14 years after the September 11, 2001 attacks.
The case of Ba Odah, who was transferred to Guantanamo in 2002, has created divisions within the US administration.
Officials from the Defence Department, which administers the centre, called for government lawyers to oppose a habeas corpus petition, which Ba Odah’s lawyers filed in June, requesting his release on health grounds.
Pentagon officials said transferring Ba Odah could create an incentive for future hunger strikes. State Department officials supported his release.
Omar Farah, Odah’s defence lawyar, said the decision indicated that President Barack Obama is unable to control growing divisions in his administration and achieve his goal of closing the Guantanamo detention facility before he leaves office in 2017.
Farah, said the filing, which was sealed, reflected the White House’s inability to develop a coherent approach to transfer Ba Odah and 51 other detainees cleared for release.
“It is a transparent attempt to hide the fact that the Obama administration’s inter-agency process for closing Guantanamo is an incoherent mess,” said Farah, a laywer with the Centre for Constitutional Rights.
“And it is plainly intended to conceal the inconsistency between the administration’s stated intention to close Guantanamo and the steps taken to transfer cleared men.”
Amnesty International USA also condemned Friday’s decision.
Lawyers specialising in national security said they were unable to think of a case where the government had filed a sealed challenge to a habeas petition.
A Justice Department representative said the filing was sealed because it contained medical information.
The filing was not intended to slow the transfer of Ba Odah out of Guantanamo and a public version of the filing would be released, the representative said.
Defence secretary waiver
Lawyers for Ba Odah, who was captured by the Pakistani Army along the Afghan border and was accused of receiving weapons training in order to fight with the Taliban, said Obama could have instructed government lawyers not to oppose the habeas petition.
There are as many as a half dozen other habeas petitions that the government could choose not to contest.
The lawyers said Ba Odah was a test case for how the president could transfer more of the 52 detainees who have been cleared from release but remain in Guantanamo.
Such releases avoid a congressionally mandated requirement that the Secretary of Defence personally sign a waiver approving each transfer.
The signed waiver requirement, and intense opposition to releases from top military commanders, has resulted in successive defence secretaries being slow to transfer detainees cleared for release.
Obama has said he is determined to close the camp, which has been condemned internationally because of the harsh treatment of detainees, but Republicans in Congress have passed laws preventing the president from transferring any inmates to US soil.