WASHINGTON (AFP) – The raid that took down Osama bin Laden is thought to have involved one special operative -- a highly-trained military dog, part of an elite corps not to be confused with a family pet.

The US military has refused to confirm if a dog was involved in Monday's helicopter-borne mission deep inside Pakistan, but those familiar with military dogs said only an animal with special breeding and training could have taken part.

"Those dogs are trained to move with the teams. They can identify the friendlies from the non-friendlies at a high rate of speed," said Mike McConnery, owner of Baden K9, a Canadian-based breeding and training firm that provides dogs for elite military units in the United States and elsewhere.

The New York Times first reported that a canine choppered in with the 79 elite US forces for the operation in Abbottabad, 50 kilometers (30 miles) from Islamabad, where bin Laden was finally sniffed out after a decade-long manhunt.

US military officials said they could not discuss anything related to tactics, procedures or protocol, including the deployment of dogs.

"If there were a dog, and I'm not saying there was... We're not doing any interviews," said Major Wes Ticer, spokesman for Special Operations Command.

McConnery said even if he were familiar with any purported dog hero, he was muzzled, unable to discuss it for fear of revealing military tactics.

But he said that for a mission such as the one in Pakistan, a dog would need to have skills and training well above those canines already used in many law enforcement or rescue operations.

"They are much more than ball-chasing creatures, they are soldiers," he said.

It was most likely that any dog involved in the raid would have been either a Belgian Malinois or Dutch Shepherd, being among the few breeds with the right skills and temperament for such a mission.

German Shepherds have been used in the past for similar missions, he said, but few are available now with the right breeding and training for such a delicate mission.

"It would be a Malinois or Dutch Shepherd," McConnery said.

"They are dogs that can go from zero to 100 miles an hour in a second. They have catlike agility, and a high level of communication with the handler at a high level of stress... That's a totally different animal than what you see in law enforcement."

In the mission, McConnery said the elite dog could have been used "as a distraction and as a probe."

"If you see my dog coming, you can shoot my dog or you can shoot at me," he said. "If you shoot at my dog I will shoot you. If you shoot me, the dog will get you. This draws the attention of the bad guys and gives you a few seconds to make that entry."

Some media reports suggest the dog could have been a "combat tracker" trained to sniff out individuals, similar to the canines that tracked down Iraqi leader Saddam Hussein hiding in an underground hole.

The Times speculated that the dog used in Abbottabad could have been used to thwart any attempted escape from the fortified compound.

Master Sergeant and dog trainer William Gaskins told MSNBC that the 2,700 dogs used by the US military are a key component of the American fighting force.

"The dogs' sense of hearing is key," he said.

Sometimes "the first... to enter the building will be the dog," Gaskins added.

If the enemy puts explosives behind a door, the use of dogs "would allow the team to enter safely because the dog has swept that door before they enter."

Dogs have been used throughout history by military forces, and in the United States since the Civil War. The US Army Canine Corps was formed during World War II and grew to as many as 10,000 at the time.

Military war dogs -- MWDs -- include mostly German Shepherds, Dutch Shepherds and Belgian Malinois but also Golden Retriever, Labrador Retriever and other sporting breed dogs have been used for some search missions, according to the Defense Department.

"The German Shepherd and Belgian Malinois have the best overall combination of keen sense of smell, endurance, speed, strength, courage, intelligence and adaptability to almost any climatic condition," a fact sheet says.

The US military has dramatically expanded the use of dogs in Afghanistan to sniff out lethal homemade bombs, which are the main cause of casualties among the NATO-led force.

"They are unsung heroes because every day they are out there, saving the lives of our troops," said Gerry Proctor, spokesman for the Lackland Air Force Base in Texas where most military dogs are trained.

McConnery said any dog accompanying the Navy SEALs would have had to be a member of a team, able to work with all the commandos, not just a single handler.

"If someone goes down, the dog still has to function," he said.

Because of their unusual characteristics, an elite military dog could not be transformed into a household pet, says McConnery.

"The dogs at this level could not become pets," he said. "We have had retired dogs come to live out their lives here at our facility, some go with the soldiers and become part of their families. They are not discarded by any means."