Surgeons are considering how much of a boy's ear can be repaired after he was attacked by a pit bull type dog.
It is illegal to own pit bull terriers in Northern Ireland
The 12-year-old had part of his ear bitten off at Upper Stanfield Street in Belfast on Thursday. He was taken to hospital and later discharged.
Animal charity, the USPCA, said the dog had been voluntarily surrendered to them and had been put down.
USPCA chief executive Stephen Philpott said part of the ear had to be retrieved from the dog's stomach.
"Police contacted us. They then asked us to try and get that animal to a veterinary surgeon and to get the ear, if it could be retrieved, to the Ulster Hospital," he said.
"That procedure was started. But our officers were stood down when the hospital told us that, in their opinion, that would not be possible.
"We were then told to basically help with an evidence gathering situation and to retrieve any foreign matter from the dog. That was done last night."
Mr Philpott said his officers were stunned at the severity of the attack.
"The society has issued countless warnings on the proliferation of dangerous dogs in our communities and the inevitability of incidents such as this," he said.
The boy was out playing in the street when he was attacked
"In some cases we have been ridiculed by the very people charged with administering the Dangerous Dogs Act, however, we cannot stand idly by whilst the threat posed to animal welfare and personal safety by dangerous dogs is not being adequately addressed."
Sinn Fein assembly member Alex Maskey said pit bulls cannot be kept in residential areas.
"If it had not been for the courageous efforts of a local community worker, I believe that the injuries could have been even more severe," he said.
It has been illegal to own pit bull terriers in Northern Ireland since 1976 as they are a proscribed breed under the Dangerous Dogs Act. However, it is still legal to keep the breed in the Republic of Ireland.