Secretary of Defense Chuck Hagel said the operation to free Sgt. Bowe Bergdahl was not relayed to Congress because officials believed the soldier's life was in danger and the military had to move quickly to get him safely out of Afghanistan.

The sole American prisoner of war held in Afghanistan was flown to a U.S. military hospital in Germany on Sunday after being freed in a swap deal for five Taliban militants who were released from the Guantanamo Bay prison in Cuba.

Army Sergeant Bowe Bergdahl had been held for nearly five years and his release, following years of on-off negotiations, suddenly became possible after harder-line factions of the Afghan Taliban shifted course and agreed to back it, U.S. officials said.

U.S. Defense Secretary Chuck Hagel said he hoped the exchange might lead to breakthroughs in reconciliation with the militants and rejected accusations from some Republicans it resulted from negotiations with terrorists, saying the swap had been worked out by the government of Qatar.

"We didn't negotiate with terrorists," Hagel said in an interview on NBC's "Meet the Press". "As I said and explained before, Sergeant Bergdahl was a prisoner of war. That's a normal process in getting your prisoners back."

Bergdahl, 28, was handed over at about 6 p.m. local time on Saturday to U.S. forces who had flown in by helicopter. The Afghan Taliban said they had released Bergdahl near the border with Pakistan in eastern Afghanistan.

He arrived at Landstuhl Regional Medical Center in Germany on Sunday. After receiving care Bergdahl would be transferred to another military medical facility in San Antonio, Texas, U.S. defense officials said, without giving a date for his return to the United States.

His parents, appearing at a news conference in Boise, Idaho, were clearly aware of the long task ahead as Bergdahl adapts to being free, saying he needed time to decompress and his recovery was a "work in progress."

Bob and Jani Bergdahl said they had not yet spoken to their son. They began the news conference with an open message to him, saying how much they loved him and admired his resilience through the long years of captivity.

Bergdahl, from Idaho, was the only known missing U.S. soldier in the Afghan war that began soon after the Sept. 11, 2001 attacks on the United States to force the Taliban - accused of sheltering al Qaeda militants - from power.

He was captured in unknown circumstances in eastern Afghanistan on June 30, 2009, about two months after arriving in the country.

Many U.S. government officials believe Bergdahl was captured after walking away from his unit in violation of U.S. military regulations. But a U.S. official has strongly suggested that Bergdahl was unlikely to be disciplined.

"Our mission now is getting Sergeant Bergdahl healthy and back to his parents," the official said.


U.S. President Barack Obama hailed the release in an appearance with Bergdahl's parents on Saturday in the White House Rose Garden, saying that "while Bowe was gone, he was never forgotten".

In exchange for Bergdahl's freedom, the U.S. released five Taliban detainees from Guantanamo. A senior Gulf source confirmed they had arrived on Sunday in Doha, capital of Qatar, the Gulf emirate that acted as intermediary in the negotiations.

They would not be permitted to leave Qatar for a year, the source said, adding that their families had been flown from Afghanistan.

Qatari Foreign Minister Khaled al-Attiyah said Qatar got involved in the case because it was a "humanitarian cause".

U.S. officials referred to the release of the Taliban detainees as a transfer and said the restrictions placed on them included monitoring of their activities.

Those assurances were greeted with skepticism by U.S. Republicans and some Afghan officials, who voiced concerns that the men, described as senior Taliban figures, would rejoin the insurgency against the government in Kabul.

"They will be very dangerous people, because they have connections with regional and international terror organizations around the world," a senior Afghan intelligence official said.