A Colombian drugs network has been trying to smuggle heroin into the US by surgically implanting it into pedigree puppies, US drugs agents have said.
Six puppies were found with liquid heroin stitched into their bellies
In one case, 14 packets of liquid heroin were found sewn into the bellies of six Labrador puppies by a vet.
The network also allegedly used human couriers, who either swallowed or hid the drugs in a variety of containers.
The Colombian authorities, working with the US Drug Enforcement Administration (DEA), have arrested 22 people.
The gang's alleged activities were revealed when local and US agents who raided a farm in Colombia found 10 puppies, six with scars on their bellies, the DEA said.
Ultrasound scans revealed the packets, weighing about 3kg (7lbs) and worth some $200,000 (£113,000), inside those dogs.
Three of the puppies died as a result of infection after the drugs were removed but three survived and are said to be "alive and well".
John Gilbride, head of the DEA's New York office, said it remained unclear how many dogs may have been used by the gang.
"I think it's outrageous and heinous that they'd use small, innocent puppies in this way," he said.
Ultrasound scans revealed heroin packets inside the dogs with scars
"It just demonstrates what lengths drugs dealers will go to get drugs into the country."
The network, based in the Colombian city of Medellin, allegedly used puppies and other methods to transport drugs on commercial flights into New York and across the eastern US.
Heroin was also found in moisturising creams, aerosol cans, pressed into bead shapes and stitched into the lining of purses and luggage, US agents said.
The DEA, which backed the two-year investigation by the Colombian authorities, hopes to extradite some of the suspects to face charges in the US.
Colombia is the main supplier of heroin to the US.