PARIS - US Sgt. Bowe Bergdahl has told people treating him at an American military medical facility in Germany that he was tortured, beaten and held in a cage by his Taliban captors in Afghanistan after he tried to escape, a senior US official said Sunday.

The official spoke on condition of anonymity because he was not authorized to discuss what Bergdahl has revealed about the conditions of his captivity.

The official said it was difficult to verify the accounts Bergdahl has given since his release a week ago.

Bergdahl, now 28, was captured in June 2009 after he disappeared from his infantry unit. He was held for nearly five years by Taliban militants.

The New York Times reported Sunday that military doctors at the Landstuhl Regional Medical Center say that while Bergdahl is physically able to travel he's not yet emotionally prepared to be reunited with his family. He has not yet spoken to his family.

It's unclear when he may get to go home.

Typically, a returned captive would spend from five days to three weeks in the phase of reintegration in which Bergdahl now finds himself, according to a Pentagon psychologist who is an expert in dealing with military members who have been released from captivity said this past week. The psychologist spoke to reporters Thursday on condition of anonymity under ground rules set by the Pentagon.

Once Bergdahl is considered ready to move on to the next phase of his decompression, he is expected to be flown to an Army medical center in San Antonio, where it is believed he will be reunited with his family.

Bergdahl was returned to the US military in exchange for the release of five Taliban militants from the US military prison at Guantanamo Bay, Cuba.

"It would have been offensive and incomprehensible to consciously leave an American behind, no matter what,'' Secretary of State John Kerry said.

Qatar, a tiny Gulf state, served as a go-between during the negotiations, and has ongoing role in ensuring the five released prisoners remain there for at least a year, under a memo of understanding with the US

The Qataris aren't "the only ones keeping an on eye on them,'' Kerry said in an interview broadcast Sunday on CNN's "State of the Union.''

He said the US has confidence in the restrictions imposed on the former detainees, as a condition of their release.

"I am not telling you that they don't have some ability at some point to go back and get involved'' in the terrorism fight against the United States, Kerry said.

"But they also have an ability to get killed doing that, and I don't think anybody should doubt the capacity of the United States of America to protect Americans. ... So these guys pick a fight with us in the future or now or at any time at enormous risk,'' Kerry said.

The deal, which the Obama White House brokered without consulting Congress, ignited a political firestorm that shows no signs of abating.

Lawmakers, both Republicans and Democrats, who initially praised Bergdahl's release, backed off amid questions about whether he was a deserter who walked away from his post and an outcry over the exchange. Some of Bergdahl's fellow soldiers maintain that Americans died during efforts to find and save him.

On Wednesday, Bergdahl's hometown of Hailey, Idaho, abruptly canceled plans for a welcome-home celebration, citing security concerns. And on Saturday the FBI said Bergdahl's family had received threats that are being investigated by federal, state and local authorities.

The US official told the AP that Bergdahl's parents were being harassed and threatened, including death threats.