The Pentagon broke the law when it swapped five Taliban leaders for Bowe Bergdahl earlier this year, an independent government watchdog agency said on Thursday.  The Government Accountability Office's opinion said that the Department of Defense violated the law when it did not notify the relevant congressional committees 30 days in advance of the transfer. It also ruled separately that the Pentagon broke the Antideficiency Act when it paid for the swap using funds that were not technically available.

The swap cost the White House $988,400, none of which was intended to pay for the prisoner trade. The costs covered Bergdahl’s pick up in Afghanistan and the transfer of five Taliban leaders from Guantanamo Bay, Cuba to Qatar, where they will stay for the remainder of the year.

Defense Secretary Chuck Hagel told congressional leaders about the trade only the day it happened, according to the Associated Press.

Not only must Congress be notified at least 30 days prior, they must also be provided with “detailed statement of the basis for the transfer or release” and an “explanation of why the transfer or release is in the national security interests of the United States,” according to National Defense Authorization Act.

The DOD defended its actions and told the GOA that notifying Congress any earlier “would have interfered with the Executive’s performance of two related functions that the Constitution assigns to the President: protecting the lives of Americans abroad and protecting U.S. service members.” 

"When DOD [Department of Defense] failed to notify specified congressional committees at least 30 days in advance of its transfer of Guantanamo Bay detainees to Qatar, DOD used appropriated funds in violation of section 8111," the report said.

The GAO said that the "DOD has dismissed the significance of the express language" in the law. 

Congressional lawmakers complained after the news broke of the Bergdahl swap that the five Taliban leaders released could potentially cause harm to the United States. As part of the swap, the former Guantanamo leaders will spend a year in Qatar before being allowed to move elsewhere. 

Sen. Lisa Murkowski, R-Alaska, one of the lawmakers who requested the report, said Thursday in a prepared statement that the president “clearly defied” the law.

“We have all seen the President decide to override the concept of checks and balances in many questionable executive actions, but the GAO opinion confirms that by doing so in connection with the release of Bowe Bergdahl, he engaged in a clear violation of the law,” said the statement. “I hope this opinion by the nonpartisan Government Accountability Office sends a clear signal to the President that his recent shift towards unilateral action is not consistent with this nation's principles and our carefully designed separation of powers."

It's currently uncertain whether any kind of legal action will come from the report, although the House Armed Forces Committee has prepared a “resolution of disapproval,” which will be considered later this year. 

Alessandria Masi contributed to this report.