Released Taliban captive Sgt. Bowe Bergdahl has been taken to the Brooke Army Medical Centre in Texas where he will begin the next phase of his "reintegration process", the Pentagon said.
In a statement released by Pentagon Press Secretary Rear Adm. John Kirby, he said:
"Secretary Hagel is confident that the army will continue to ensure that Sgt. Bergdahl receives the care, time and space he needs to complete his recovery and reintegration."
US army Sgt. Bowe Bergdahl, freed by the Taliban after five years in captivity, has arrived at a Texas military base, the Pentagon has said.
Bergdahl has been recovering in Germany and is now due to be taken to the Brooke Army Medical Centre for treatment.
The FBI is investigating threats against the family of former Taliban prisoner Sgt. Bowe Bergdahl.
The threats come after a number of former comrades of Bergdahl made television appearances accusing him of being a "deserter".
His home town was forced to cancel plans for a welcome-celebration for the soldier, who has been released after five years of captivity in Afghanistan, due to security concerns.
Hailey, Idaho, a town of 8,000, where Sgt Bergdahl's parents, Bob and Jani Bergdahl, live, has been swamped with hate mail and angry calls. FBI spokesman William Facer said:
"The FBI continues to monitor the situation in Hailey, Idaho. We are working jointly with our state and local partners and taking each threat seriously."
The former pastor of the parents of a US soldier released from Taliban captivity after nearly five years says they have been "really hurt" by claims that he was a traitor and the outpouring of anger towards their family.
Pastor Phil Proctor of Sterling Presbyterian Church in Sterling, Virginia, said Bob and Jani Bergdahl were surprised by interviews they had seen with former platoon mates of their son Bowe.
Proctor said the Bergdahls, who live in Idaho, have yet to speak to their son, who is currently recovering at a military hospital in Germany.
Hillary Clinton's new book has revealed that Barack Obama's government demanded the release of captured US soldier Sgt Bowe Bergdahl in every prisoner discussion it held with the Taliban.
The former US secretary of state also says in her book, Hard Choices, that she recommended President Obama end the decades-long US embargo on Cuba to force Fidel and Raul Castro into democratic change.
Celebrations due to be held in Idaho, the hometown of US army Sgt Bowe Bergdahl, have been cancelled.
Bergdahl was released after five years in Taliban captivity amid controversy over the circumstances surrounding his capture.
US Secretary of Defence Chuck Hagel said it was unfair to jump to conclusions about released captive Sgt Bowe Bergdahl until the circumstances around his capture by the Taliban had been reviewed.
Mr Hagel said:" "We don't do that in the United States. We rely on facts.
"It's not my place as a former sergeant in the Army to decide who's worthy of being a sergeant and who isn't."
Sgt Bergdahl had been held in Afghanistan for five years but was released on Saturday amid speculation that he might face desertion charges.
Mr Hagel said the army would review all the circumstances surrounding how he left his unit and was captured by the Taliban.
Pentagon spokesman John Kirby told NBC News there was "no reason to doubt the authenticity" of the clip purporting to show US soldier Sergeant Bowe Bergdahl, who has spent five years in Taliban captivity, being handed back into US custody.
He said: "US officials are currently reviewing the video, but our focus right now is in getting Bergdahl the care he needs."
A video shot by the Taliban appears to show US soldier Sergeant Bowe Bergdahl, who has spent five years in Taliban captivity, being handed back into US custody.
The footage shows Bergdahl sitting in a silver pick-up truck before getting out of the vehicle with a plastic bag and being frisked before being taken away in a helicopter.
Armed men can be seen on the hillside above him as one of his escorts waves a white flag.
The US Army may still pursue an investigation that could lead to desertion or other charges against Sergeant Bowe Bergdahl, who was freed from five years of Taliban captivity in a prisoner exchange last weekend, General Martin Dempsey, chairman of the Joint Chiefs of Staff said.
Speaking publicly for the first time about the case, Gen Dempsey said he does not want to prejudge the outcome of any investigation or say anything that might influence a commander's decision.
But he said US military leaders "have been accused of looking away from misconduct, and it's premature" to assume they would do so in Sgt Bergdahl's case, despite the soldier's five years as a Taliban prisoner.