By Phil Stewart

WASHINGTON (Reuters) - A U.S. general will decide whether to pursue disciplinary action against Sergeant Bowe Bergdahl over his 2009 disappearance from his base in Afghanistan, after the Army said on Monday it forwarded the findings of its investigation to him.

General Mark Milley, head of U.S. Army Forces Command, would determine "appropriate action - which ranges from no further action to convening a court martial," the Army said in a brief statement.

Bergdahl was released in May in a prisoner swap with the Taliban after five years in captivity. Some of his fellow soldiers in Afghanistan have branded him a deserter, saying he intentionally left his post before being captured by the enemy.

The Army declined to discuss the conclusions of the investigation, which were briefed to U.S. Defense Secretary Chuck Hagel last week.

"The Army cannot discuss or disclose the findings of the investigation while disciplinary decisions are pending before commanders," the Army said.

Bergdahl's attorney, Eugene Fidell, declined to discuss the case but said he looked forward to reviewing the investigation.

"I assume at some point the Army will furnish us with a copy of the investigation," Fidell told Reuters.

Republican lawmakers reacted with outrage to the deal that brought Bergdahl home, demanding hearings over why the White House had failed to give Congress adequate notice before freeing prisoners from the U.S. detention facility in Guantanamo Bay, Cuba.

The Government Accountability Office said the Pentagon broke the law by using money appropriated by Congress to carry out the transfer of Guantanamo prisoners without giving lawmakers the required 30-day notice.

It is unclear what punishment the Army might pursue for Bergdahl should it find the need for disciplinary action.

Any conclusions that he broke the U.S. military's rules could have financial consequences for Bergdahl, potentially forcing him to forfeit hundreds of thousands of dollars in backpay accumulated during his captivity, and future benefits he might be entitled to in the future.

(Reporting by Phil Stewart; Editing by Bill Trott)