Shortly after taking office, President Barack Obama issued an order to shutter the facility by January 2010
The US government has published for the first time a list of 55 Guantanamo detainees cleared for release but still held amid challenges identifying a willing host country or concerns about sending them home.
The list, which includes names and serial numbers, represents about a third of the 167 "war on terror" suspects who still linger at the US naval base in southern Cuba more than 11 years after the September 11, 2001 attacks on US soil.
A significant number of the men listed are Yemenis, reflecting US concerns over sending Guantanamo detainees to the troubled nation, where they could become involved in terror-related activities.
President Barack Obama suspended transfers to Yemen in January 2010, citing the "unsettled" security situation there.
Since 2009, government officials have kept secret the identities of detainees approved for release or transfer, saying a public release would hinder diplomatic efforts to arrange for the men to be moved to "safe and responsible" locations.
"The United States originally sought protection of this information in order to maintain flexibility in its diplomatic engagements with foreign governments on potential detainee transfers, especially in cases of resettlement in third countries, rather than the detainees' respective countries of origin," a Justice Department spokesperson said Friday.
But in a court filing in the US District Court for the District of Columbia in the capital Washington, government lawyers said "circumstances have changed" such that prisoners' names "no longer warrant protection."
The efforts of the United States to resettle Guantanamo detainees have largely been successful," they said, noting that 28 prisoners have been sent to their home countries since 2009, while 40 prisoners have been transferred to other countries.
Among the prisoners cleared for release was Shaker Aamer, the last British resident held at Guantanamo, and the prison's five remaining Tunisians. London has repeatedly called for Aamer to be freed.
Missing from the list was Adnan Latif, a 32-year-old Yemeni man who died at Guantanamo earlier this month, the ninth prisoner to pass away since the prison camp was opened in 2002.
Shortly after taking office, President Barack Obama issued an order to shutter the facility by January 2010. But his plans quickly fell apart amid staunch opposition from Congress, as lawmakers raised security concerns.
Although Congress has placed restrictions limiting prisoner transfers to other countries or on US soil, the Obama administration has sought help from allies willing to take in qualified detainees.
Rights groups were quick to hail the new list's publication, with the American Civil Liberties Union calling it a "partial victory for transparency" that should also be a "spur to action."
"These men have now spent three years in prison since our military and intelligence agencies all agreed they should be released," ACLU senior staff attorney Zachary Katznelson said in a statement. "It is well past time to release and resettle these unfairly imprisoned men."
Amnesty International USA executive director Suzanne Nossel said the cleared detainees "should be immediately transferred out of Guantanamo to countries that will respect their human rights... Indefinite detention is a human rights violation and it must end."
The disclosure "dispels the myth that the remaining detainees who are trapped at Guantanamo are too dangerous to be released," said the Center for Constitutional Rights, which represents some Guantanamo prisoners.
"The list announced today, however, is incomplete, and not appearing on the list is no indication of wrongdoing," CCR executive director Vincent Warren added.