For the first time in the history of the world's most famous sled dog race, several of the high-performance animals have tested positive for a prohibited drug.
But race officials have refused to name the musher involved in the iconic Iditarod.
The governing board of the nearly 1000-mile (1600km) race said in a statement that several dogs tested positive for the opioid pain reliever Tramadol.
Officials said the team was tested six hours after finishing the nearly race in Nome in March.
The name of a musher with several dogs that tested positive for a prohibited drug is not being released, based on an attorney's advice.
Iditarod Trail Sled Dog Race spokesman Chas St. George says the musher also has not been named because of the unlikelihood that race organisers could prove the musher intentionally administered the drug.
St. George says the musher will be allowed to participate in next year's race and will not face any disciplinary actions.
