The USPCA said the dogs, which had seriously scarred faces, were seized in a joint operation yesterday involving Banbridge District Council, the PSNI and the animal welfare charity.

A USPCA spokesman said: “Nine facially scarred pit-bull dogs have been removed from the premises and a dog-fighting ring was uncovered together with training equipment and a supply of steroids used to build muscle bulk and heighten aggression in dogs used for fighting.”

He said investigators were surprised to discover that steroids found at the scene had been manufactured in Iran.

“It just shows you what lengths some people will go to in order to pursue dog-fighting,” the spokesman said.

There was nobody at the rental property when the raid occurred, but a USCPA spokesman said it had now been well established that there is a ring of active pit-bull breeders and fighters in the Katesbridge area. He said the operation had been mounted after a tip-off.

Items recovered included a ring in which the dog-fight competitions are held and neck weights which the dogs wear while running on specially created treadmills in order to improve strength and endurance.

Independent Unionist councillor Stephen Herron condemned those behind the fighting ring.

“It is simply disgraceful people would breed dogs for such a barbaric sport,” he said.

“I would praise the council, USPCA and police for their good work in bringing this to light.

“Hopefully they can also bring charges and someone will eventually be made amenable.”

The operation followed the case of five-year-old Ellie Lawrenson, mauled to death by a pit-bull on New Year’s Day. Ellie was killed by her uncle’s pit-bull terrier at her grandmother’s house in St Helens. The one-year-old dog, called Rueben, was shot dead after the attack in which Ellie’s grandmother was also hurt.

There have been a string of dangerous dog amnesties in Northern Ireland since then, including Ballymena and Londonderry.

A police spokeswoman said officers in Banbridge in a joint operation with the USPCA attended an address in the Katesbridge area yesterday afternoon.

“Following a search of the property it is understood that a number of dogs, thought to be pit bull, were seized under the dangerous dogs legislation, along with other items,” she said.

“It is also understood that amongst the other items discovered, equipment that may be used for the purpose of dog fighting was found.”

She urged anyone with information to contact police in Banbridge on 0845 600 8000 or Crimestoppers on 0800 555 111.