(Adds Bergdahl family statement)
By Missy Ryan, Phil Stewart and Warren Strobel
KABUL/WASHINGTON, Feb 18 (Reuters) - The Obama administration is taking steps it hopes could lead to a resumption of peace talks to end the Afghan conflict, including reviving a proposed swap of Taliban detainees held at Guantanamo Bay in return for a U.S. prisoner of war.
According to Western officials familiar with the matter, President Barack Obama's senior aides in late December resolved to renew attempts to arrange the prisoner exchange with the goal of jump-starting negotiations stalled since last June.
The hope is that the exchange could open the door to more substantive peace talks on Afghanistan's future.
Reuters has learned that, to further the initiative, U.S. officials also have held meetings with the government of Qatar, which has played a mediating role during several years of on-and-off peace efforts, officials said.
The White House last month sent out a team of officials, including the Pentagon's chief lawyer, Stephen Preston, to Doha to ensure that the Qatari government remained willing to host the Taliban detainees who might be sent there from Guantanamo Bay, the officials said.
Government officials in Qatar reaffirmed that they would support the transfer under the same conditions as envisioned in previous discussions, the sources said. U.S. conditions in the past have included preventing the Taliban members from traveling outside of Qatar.
Under the plan, Taliban-linked militants would return U.S. Sergeant Bowe Bergdahl, who was stationed in Paktika province in eastern Afghanistan when he disappeared under unclear circumstances on June 30, 2009, about two months after arriving in the country.
In another step toward restarting a peace process, Qatar provided U.S. officials a video showing Bergdahl, which it obtained from the Taliban, to confirm he remained alive despite his more than four years in captivity.
News of the video, which U.S. officials said showed Bergdahl appearing to be in "declining health" but not gravely ill, surfaced last month, but the footage has not been made public. U.S. officials said they believed the video was filmed late last year.
The Daily Beast website reported last week that the U.S. government had sought the video as proof Bergdahl was still alive. The site also said that a possible exchange of prisoners was part of a U.S.-backed effort to reach an agreement with the Taliban.
U.S. officials believe Bergdahl, the only known U.S. soldier to remain missing in the war in Afghanistan, is being held in northwest Pakistan by Taliban-linked militants. Several officials said they believe the militants holding Bergdahl are under strict instructions not to harm him because of the possibility of a prisoner trade.
"Clearly if negotiations with the Taliban do resume at some point then we will want to talk with them about the safe return of Sergeant Bowe Bergdahl. He has been gone far too long, and we continue to call for and work towards his safe and immediate release," said White House spokeswoman Caitlin Hayden.
The White House declined comment on the recent U.S. discussions with Qatar and the video of Bergdahl.
While the United States has signaled that it is interested in resuming discussions, the Taliban have not yet responded, officials said.
In a statement distributed by the U.S. military, Bergdahl's family responded to the renewed diplomatic efforts to secure the soldier's freedom: "We welcome this development and we applaud the unity of purpose and resolve at the White House and the other U.S. government agencies involved. ... We are cautiously optimistic these discussions will lead to the safe return of our son after more than four and a half years in captivity."
NEW CIVIL WAR PROSPECT
U.S. attempts to arrange peace talks between the Taliban and Afghan President Hamid Karzai's government have collapsed at least twice in the past. It is far from clear that the Western-backed Afghan government and the reclusive Islamist Taliban could reconcile their vastly different visions for the country's future.
The stakes appear higher now because Karzai is declining to sign a security agreement between Kabul and Washington that would permit foreign troops to stay in Afghanistan beyond the end of 2014. That has raised the prospect of renewed civil war.
NATO officials have long said the Afghan conflict will ultimately be settled at the negotiating table rather than on the battlefield.
"We still maintain that," said a Western official in Kabul, speaking of the peace process generally. "For that to happen, you need the Taliban and the elected government, whoever it is, to sit down and talk to one another." The official spoke on condition of anonymity.
Previously, U.S. officials held numerous meetings with Tayeb Agha, a former secretary to Taliban leader Mullah Omar and still close to him. Renewed meetings with Agha would be a key next step.
A host of things could go wrong, as they have in the past.
Last summer, in what appeared to be a breakthrough, the Taliban announced it was opening an office in Doha to facilitate peace talks.
But hopes were dashed when the Taliban raised their flag and declared the office an outpost of the Islamic Emirate of Afghanistan, a reference to the group's repressive rule from 1996 to 2001. Karzai's government was furious and called off its participation in planned talks in Qatar.
The renewed U.S. initiative does not appear to be linked to an attempt by the Afghan government to kindle its own peace process.
The possibility that the White House might send senior Taliban detainees to a third country under unclear custody circumstances has provoked a backlash from U.S. lawmakers in the past and could do so again.
The five prisoners include Mohammed Fazl, a former senior commander of the Taliban army held since early 2002. Not all are military figures: Khairullah Khairkhwa is a former Taliban regional governor who is seen by American officials as less dangerous than some others.
The Afghan government's decision last week to release 65 inmates that Washington insisted were dangerous Taliban militants angered U.S. military leaders and lawmakers. It could make it harder for the White House to argue for transferring much-higher-level Taliban figures out of U.S. custody. (Additional reporting by Mark Hosenball and Lesley Wroughton in Washington, Amena Bakr in Doha and Hamid Shalizi in Kabul. Editing by Prudence Crowther)