KABUL, Afghanistan - The Taliban released a video yesterday in which Pfc. Bowe Bergdahl, a U.S. soldier captured by insurgents nearly six months ago, denounces the American military effort in Afghanistan as foolhardy and doomed to failure.

Military officials acknowledged that the man shown in the video was Bergdahl, 23, and asserted that he spoke under duress.

Rear Adm. Gregory Smith, chief spokesman for the NATO forces, called the 36-minute video a "horrible act which exploits a young soldier, who was clearly compelled to read a prepared statement."

Bergdahl's family, of Hailey, Idaho, in a statement issued through Lt. Col. Tim Marsano of the Idaho National Guard, urged the captors "to let our only son come home."

To their son, the family said: "We love you and we believe in you. Stay strong."

Bergdahl, an Idaho native and a member of an infantry unit based at Fort Richardson, Alaska, is the only U.S. service member known to have been seized by insurgents during the eight-year Afghan conflict.

He vanished June 30 from his base in eastern Afghanistan's Paktika province, bordering Pakistan. Military authorities acknowledged at the time that Bergdahl was believed to have walked away from his post for unknown reasons.

The remote base where he was stationed lies in an area where the Taliban and other insurgent groups operate freely. Some of the 30,000 American troops being sent to Afghanistan in 2010 are expected to be deployed in the east, along with the volatile south.

Bergdahl had not been heard from since July 19, nearly three weeks after his capture. At that time, his captors released a video showing him clad in traditional Afghan dress, appearing distraught, calling for a withdrawal of American troops from Afghanistan.

The new video shows Bergdahl wearing what appears to be American military fatigues and a helmet, his eyes shielded by large sunglasses. While pale, he appears in generally good condition and says in the video that he is not being mistreated.

The Taliban announced earlier in December that a new video of Bergdahl would soon be released, and its distribution on Christmas was characterized by the U.S. military as an effort to exploit both the holiday and the soldier's captivity for maximum propaganda purposes.

"To release this video on Christmas Day is an affront to the deeply concerned family and friends of Bowe Bergdahl, demonstrating a contempt for religious traditions and the teachings of Islam," Smith said.

There was no indication of when the video was made. Because of that, a senior U.S. official said it was not regarded as proof that Bergdahl was still alive.

Military officials have said it is not known whether Bergdahl was being held in Afghanistan or in Pakistan. He has been the subject of a large-scale hunt by Western and Afghan troops on the Afghan side of the border, but search options are sharply limited in the lawless tribal areas on the Pakistani side.

U.S. troops are not supposed to operate inside Pakistan, though the United States has conducted missile strikes and at least one known ground raid in the tribal areas, and pilotless drones are used for aerial surveillance.

The Bergdahl video's technical quality is better than the one released in July, raising the possibility that his captors had moved him to what they considered a more secure location.

An English-language notation beside the image of Bergdahl speaking describes him as an American soldier imprisoned by "the mujahideen of the Islamic Emirate of Afghanistan" - what the Taliban movement calls itself.

At the start of the video, Bergdahl identifies himself by name and rank, gives his birthplace as Sun Valley, Idaho, describes himself as a captive of the Taliban, and lists his mother's maiden name and blood type.

Speaking in a measured monotone, he then launches into a lengthy critique of U.S. military actions in Afghanistan and elsewhere. "This is just going to be the next Vietnam, unless the American people stand up and stop all this nonsense," he says.

The Taliban previously threatened to kill Bergdahl unless a prisoner exchange was agreed to. That demand was repeated in the latest video by a Taliban spokesman, Zabiullah Mujahid, and Bergdahl urged that it be met.