ISAF officials in Afghanistan have confirmed a military dog went missing during a mission in December last year.
US military sources say the dog belonged to a coalition partner and the BBC understands it was working for British forces.
The Taliban earlier released footage of what they claimed was a dog they captured from US troops.
They said the dog, apparently called Colonel, was wearing a GPS tracking device, a torch and small camera.
Looking rather mournful, on a lead being held by a long-haired Taliban fighter, the small reddish-brown dog was paraded for a Taliban cameraman, reports the BBC's David Loyn in Kabul.
The Taliban said the dog was taken during a night raid in Laghman in eastern Afghanistan in late December.
The insurgents also showed off captured weapons of a type frequently used by American special forces.
Our correspondent says there were local reports a few weeks ago that a senior Taliban commander in the area was seen with a "foreign dog".
But the video is the first positive sighting.
Coalition forces have long used sniffer and protection dogs in Afghanistan, mostly German shepherds, Labradors or spaniels.