A five-year-old boy is being treated in hospital after being mauled by a dog taken into school as a last day of term treat.
The attack took place in the playground at Carniny Primary in Ballymena at around 9am on Friday.
Although under staff supervision at the time the dog, believed to by a husky-type animal, attacked the boy leaving him with a facial injury.
The boy was rushed to the Ulster Hospital on the outskirts of Belfast for emergency treatment to facial injuries.
Raymond Ross, principal of Carniny Primary School on the outskirts of Ballymena, said the animal had unexpectedly "turned" on the schoolboy.
"The dog was in a very controlled position. A number of children had the opportunity to stroke the dog and then suddenly the dog turned on the little child, as if it flicked its head to one side and caught the child in the face," he told the BBC.
Four adults were present at the time of the attack.
A spokeswoman for the hospital said his family had requested no publicity.
Ballymena Borough Council confirmed the dog had been humanely destroyed this afternoon.
A statement said: "Our thoughts are with the child and his family at this distressing time.
"A representative from Environmental Health attended the school following the incident and, having liaised with those involved, instigated appropriate actions to seize the dog.
"The dog has now been put down.
"Ballymena Borough Council is working alongside all appropriate organisations to carry out a full investigation."
The Health and Safety Executive has also confirmed it has launched an investigation.
Ian Paisley, DUP MP for North Antrim, described the dog attack as shocking.
He said: "It is utterly shocking and very traumatic for the young boy. It shows that we have to be very vigilant when it comes to making sure that dogs are properly tethered at all times.
"My thoughts and prayers go out to the boy and his family."
Meanwhile, a statement from Carniny Primary School said staff had been left shocked.
"We can confirm an incident took place this morning involving a pupil and a dog. The school staff have found the incident to be very distressing. Our thoughts are with the child and his family."