WASHINGTON (AFP) – The father of a US soldier captured by the Taliban in Afghanistan pleaded for his son's captors to release him, and asked Pakistan to "diligently help," in a video posted online.

Robert Bergdahl, in a video uploaded to YouTube [shown below], said he "can remain silent no longer" about the plight of his 25-year-old son, Private First Class Bowe Bergdahl, who was captured in June 2009.

Appearing in a dark shirt and bushy long beard, Robert Bergdahl addressed leaders of the Pakistani armed forces, the Taliban, and the Haqqani militants, in comments coming just a few days after a covert US mission inside Pakistan killed Osama bin Laden.

"We give our condolences and thanks to those who have fallen for Pakistan," he said to Pakistani military leaders.

"Strangely to some, we must also thank those who have cared for our son for almost two years," he added, addressing the Taliban and Haqqanis.

"We know our son is a prisoner and at the same time a guest in your home. We understand the rationale the Islamic Emirate has made through its videos," he said, referring to the formal name of the Taliban government in Afghanistan before the 2001 US-led invasion.

"No family in the United States understands the detainee issue like ours. Our son's safe return will only heighten public awareness of this.

"That said, our son is being exploited. It's past time for Bowe and the others to come home," he said.

Mountains are seen in the background of Robert Bergdahl video, in which he utters several Arabic phrases, including a common greeting that translates to "peace be upon you."

A resident of the western US state of Idaho, Bergdahl asks that Pakistan "diligently help our son be freed from his captivity."

The Taliban released video footage in July 2009 in which Bowe Bergdahl said he had been captured when he lagged behind his patrol.

The father requested that his son be allowed to view the video, and waved to him in anticipation.

"We love you. We have been quiet in public, but we haven't been quiet behind the scenes. Continue to be patient and kind to those around you. You are not forgotten," he said.

This video was uploaded to YouTube on May 6, 2011: