President Barack Obama said Saturday the Qatari government had given the United States security guarantees over five Guantanamo Bay prisoners transferred to secure the release of a US soldier in Afghanistan.

Obama appeared at the White House with Bowe Bergdahl's parents Bob and Jani, saying "the Qatari government has given us assurances that it will put in place measures to protect our national security."

The five prisoners were named by the Taliban as Mohammad Fazl, Norullah Noori, Mohammed Nabi, Khairullah Khairkhwa and Abdul Haq Wasiq. A US State Department official also confirmed their identities.

A Taliban source in the Pakistani city of Quetta told AFP that the men had all been officials in the Taliban regime driven out of power in the US-led invasion of Afghanistan after the 9/11 attacks, and that they were influential among the Taliban ranks.

Obama did not detail exactly what security guarantees had been put in place by Qatar.

Bob Bergdahl said he could not "communicate" his emotions after Obama called him earlier Saturday to tell him and his wife their son was free.

Bergdahl said that his son was having trouble speaking English after spending so much time in Taliban captivity.

Addressing his son, Bergdahl said a common Arabic phrase uttered by Muslims before giving a speech, and a few words that appeared to be in Pashto.

"In the name of God, the most gracious, the most merciful," Bob Bergdahl said in Arabic.

"I'm your father, Bowe," he added in English after speaking the same words in Pashto from the president's podium in the Rose Garden of the White House.

Obama said that he was proud of the US forces in Afghanistan who recovered Bergdahl and for the US diplomats who helped negotiate his release.

"Sergeant Bergdahl has missed birthdays and holidays and the simple moments with family and friends which all of us take for granted," Obama said.

"But while Bowe was gone, he was never forgotten. His parents thought about him and prayed for him every single day."