WASHINGTON — The Obama administration broke the law when it exchanged five Taliban commanders held at Guantanamo Bay, Cuba, for a captive US soldier without giving Congress 30 days’ notice, according to an official review by the nonpartisan Government Accountability Office.
The GAO released its opinion Thursday, saying the Defense Department violated the Defense Appropriations Act by failing to inform lawmakers about its plan to transfer detainees in a deal to free Army Sergeant Bowe Bergdahl.
The report also said that the Pentagon ran afoul of the law by funding the prisoner swap with money not intended for that purpose. The Antideficiency Act prohibits agencies from spending congressional appropriations on un- authorized activities.
‘‘We have consistently concluded that the use of appropriated funds for prohibited purposes violates the Antideficiency Act, because zero funds are available for the purpose,’’ the GAO said.
The Pentagon argued that the transfer was lawful under a section of the appropriations act that allows the defense secretary to move Guantanamo prisoners in the interest of national security.
But the GAO said the Defense Department still had to give Congress advance notice of the action.
‘‘To read [the law] otherwise would render the notification requirement meaningless,’’ the report said.
The Pentagon disagreed with the GAO, saying the Justice Department concluded in advance that the transfer would be legal.
‘‘The administration had a fleeting opportunity to protect the life of a US service member held captive and in danger for almost five years,’’ Rear Admiral John Kirby, a Pentagon spokesman, said in a statement.
‘‘Under these exceptional circumstances, the administration determined that it was necessary and appropriate to forego 30 days’ notice of the transfer in order to obtain Sergeant Bergdahl’s safe return,’’ Kirby said.
The GAO did not issue an opinion on whether the transfer was necessary for national security.
The appropriations act requires the Defense Department to report violations of the notice requirement to Congress and the president. The agency must provide information about the nature of the offense, how it occurred, whether the department has planned any corrective actions, and whether any personnel will face discipline.
There is no statutory timeline for delivering the report, according to the GAO.
The Army is trying to determine whether to charge Bergdahl with desertion or going absent without leave, both of which are crimes under military law.
The soldier disappeared from his patrol base in Afghanistan’s Paktika province in 2009, and Taliban militants held him in captivity for five years.
He was released in May in the prisoner exchange.
Army officials said last week that they had begun the final stage of an investigation into his disappearance, but they added that a draft report could take at least three more weeks to complete.