In this April 27, 2010 file photo, a Guantanamo detainee's feet are shackled to the floor as he attends a "Life Skills" class inside the Camp 6 high-security detention facility at Guantanamo Bay U.S. Naval Base. (POOL/REUTERS)

The Egyptian government requested this week that the United States release the sole Egyptian detained at the Guantanamo Bay military prison, language that amounts to a stark demand by a country that has been among Washington’s most reliable counterterrorism allies in the Middle East.

The case of Tariq Mahmoud Ahmed al-Sawah, 54, whom the United States accuses of belonging to al-Qaeda, has the potential to become the first thorn in the relationship between the two governments since the election of Egypt’s new Islamist president.

Amr Roushdy, a spokesman for Egypt’s Foreign Ministry, said Friday that the country’s embassy in Washington had formally made the request to the State Department on Tuesday.

“He was not charged with any crime until now,” Roushdy said. “He is an Egyptian citizen detained in an illegal manner.”

The Defense Department charged Sawah in 2008 with providing material support for terrorism and conspiracy, alleging that he was a member of al-Qaeda who specialized in explosives. His case is also significant because he has become one of the most valuable informants detained at the U.S. military camp in Cuba. The charges were dropped in March and no new ones have been filed.

Army Lt. Col. Todd Breasseale, a Pentagon spokesman, said the military does not comment on individual inmates unless they are in court proceedings or are being resettled. He added that “detention in wartime until the end of hostilities has long been recognized as legitimate under international law.”

Brock Johnson, a spokesman at the State Department, said in a written statement that U.S. officials were “working with the Egyptian government on this matter.”

Roushdy did not comment on the allegations against Sawah, who has been confined for 11 years, but said that Egypt is worried about what he called the inmate’s declining health. “He’s an old man,” the spokesman added.

“We are excited that the country of Egypt has asked for Sawah to be repatriated there,” said Sawah’s military attorney, Maj. Sean Gleason. “He has a strong extended family network in Alexandria. It would be the ideal place for him.”

Egyptian analysts said the timing of the request, coming roughly a month after Mohamed Morsi became president, should come as no surprise. Morsi is a former member of the Muslim Brotherhood, a venerable Islamist group that carried out violent acts decades ago in the pursuit of political goals. The group has long since abandoned violence as a tactic.

Military documents say that Sawah was a member of the Muslim Brotherhood when he attended secondary school in the coastal city of Alexandria in the 1970s.

Khaled Abu Bakr, a member of the international lawyers group Union Internationale des Avocats, said Egypt’s ascendant Islamist groups, which rallied around Morsi, are adamantly opposed to the detention of Muslims by the United States.

“There’s no doubt, and we must be honest, that we are now before a president with a religious background,” he said, explaining that by making the demand, Morsi could be trying to deliver on his promises to Islamist voters. “Now is the time to pay the bills.”

Sawah, who is also a citizen of Bosnia, was taken into custody after he was wounded in eastern Afghanistan in the fall of 2001, according to a U.S. military summary sheet of his designation as an enemy combatant that was made public by the anti-secrecy group WikiLeaks.

The sheet says that Sawah admitted that he was a member of al-Qaeda. The military also alleged in the document that Sawah attended terror-training camps and once met the group’s leader, the late Osama bin Laden.

U.S. officials have said that Sawah is among Guantanamo's most cooperative detainees, a distinction that has earned him a few perks in custody, such as secluded housing and the right to garden, write and paint.

Egypt, which receives about $1.3 billion annually in U.S. military aid, was among Washington’s most dependable Middle East partners after the Sept. 11, 2001, attacks that sparked a worldwide hunt for members of al-Qaeda. The CIA sent terror suspects to Egypt for interrogation as part of its “extraordinary rendition” program. Egypt’s security forces had a well-known history of using torture.

The relationship between Cairo and Washington has been tested since the wintertime 2011 revolution that led to the fall of President Hosni Mubarak, and some U.S. officials have expressed concern about the future of cooperation on security matters in the post-Mubarak era.

Nabil Fahmy, dean of the School of Global Affairs and Public Policy at the American University in Cairo, said the country’s new president is probably making a statement that his administration will not be as malleable as the last one.

“Irrespective of the merits of this case, I think Egypt will be more insistent that normal legal procedures are applied on Egyptians accused of any criminal offenses abroad and this will be the new policy,” he said. “We will respect the laws of other countries when normal legal procedures are being applied.”

Julie Tate contributed to this report.