The controversial detention facility at Guantanamo Bay, Cuba, could be closed and the 166 detainees being held there could be absorbed safely by U.S. prisons, a government report says.

Many of the detainees are accused of plotting terrorist acts against the United States.

"This report demonstrates that if the political will exists, we could finally close Guantanamo without imperiling our national security," said Democratic Sen. Dianne Feinstein, the Senate Intelligence Committee chairwoman who released the Government Accountability Office study Wednesday.

The GAO study shows that U.S. prisons already hold 373 prisoners convicted of terrorism in 98 facilities across the country.

"As far as I know, there hasn't been a single security problem reported in any of these cases," Feinstein said. "This fact outweighs not only the high cost of maintaining Guantanamo _ which costs more than $114 million a year _ but also provides the same degree of security without the criticism of operating a military prison in an isolated location."

The study said there are six Defense Department prisons and 98 Justice Department prisons that could take the detainees, but it does say that existing facilities likely would need to be modified and current inmates may need to be relocated to make room for the new arrivals.

President Barack Obama ordered the closing of the Guantanamo's detention facility when he took office in 2009, but that was blocked by a Republican-led bill that cut off funding to move the detainees to the U.S. The lawmakers cited security concerns, saying the presence of the detainees would encourage terror attacks in the states or cities where they were being held.

Feinstein commissioned the study in 2008 to find out where the detainees could be held, if the White House was able to move ahead with Guantanamo's closure.