The aunt of a two-year-old girl screamed "The dog's got the baby!" after her niece was savaged by the animal as she played in her garden in England.
The girl, with two other children aged four and six, was playing in the garden of the house on Cockburn Street, Toxteth, Liverpool when she suffered a "savage" attack by one or more of the neighbour's "huge" dogs.
Her aunt, looking after the youngsters for the afternoon, fought off the attack and ran to the front of the house carrying the child as neighbours ran to help.
The animals were kept in the garden next door but got through a hole in the fence, according to locals.
Neighbours described the dogs as "XXL American Bull Dogs" which were being bred for sale.
Supt Mark Wiggins, of Merseyside Police, confirmed the breed of the dog involved is an American Bully Dog - which is not a banned breed in the UK - and there were 11 of the animals in the three-bedroom, mid-terraced property.
While it is not an offence to own one, it is to have a dog dangerously out of control in a public or private place.
The toddler suffered serious injuries to her head and body in the incident on Sunday afternoon.
A 35-year-old man from Toxteth has been arrested on suspicion of having a dangerous dog/dogs out of control.
The neighbour lived at the address with his partner and three children.
Emergency services were first called to the house at about 3.40pm on Sunday after reports a child had been bitten by a dog and a woman had also been injured.
Supt Wiggins said the attack could have been even more serious but for the intervention of the girl's aunt.
He said suspicions the owner was breeding the dogs was also a line of inquiry for police.
He said: "There were 11 dogs in that property yesterday, either in the back garden or in the house.
We know five of them were adult dogs and six of them were puppies. We have had them assessed today and we can confirm they are not a banned breed.
"But what we do know is that the dogs are, what we believe at this time, is that the dogs are American Bully dogs, and we need to do some more inquiries to establish exactly what the nature of that dog is.
"There were three young children playing in that garden at the time, aged two, four and six and that the 57-year-old auntie who was in that property, was in the garden at the same time.
"Now she's managed to get the two older children back into the property unharmed but unfortunately she's been hurt herself with minor injuries while she's been trying to protect the two-year-old.
"She (the girl) has got extensive injuries to her face, to her neck and to her body and only time will tell if she fully recovers from that attack.
"We know one, if not more, of these dogs was involved in the attack but we need to establish what went on.
"If the aunt of that two-year-old child hadn't intervened we could have been looking at a much more serious situation in this case."
He described the victim's family as traumatised and appealed to the public to report any worries about dangerous dogs or irresponsible owners to police.
He added: "If you do insist on having a dog, you should put a muzzle on it if you have it in public."
One neighbour described hearing the girl scream as the dog attacked her.
Another said she saw the aunt dash from the house carrying the girl, called Ella, screaming: "The dog's got the baby! The dog's got the baby!"
The neighbour added: "I can't even actually think about it now," and was too upset to speak further. None of the locals were willing to give their names.
The girl was treated at the scene by paramedics before being taken by air ambulance to Alder Hey Children's Hospital.
Her condition is described as serious but not life-threatening.
The aunt who rescued the child from the dogs was taken to the Royal Liverpool University Hospital where she received treatment for minor injuries.
She was later released from hospital.
Police seized five dogs and five puppies from the home of the man who was arrested.
Neighbours said the dogs were kept in cages at the back of the house.
Chief Inspector Dave Westby said: "This was a horrific attack which has resulted in a two-year-old girl suffering extensive injuries to her head and body.
"The investigation is in its early stages, but it is believed that the child was playing in the back garden of a relative's address with two other children, aged four and six years, when a number of dogs from a nearby house managed to get in to the garden.
"At this stage it is believed that the little girl was attacked by more than one dog, and officers are trying to establish how many dogs were involved in the incident.
"Fortunately, a relative who was in the house was able to rescue the child from the dogs.
"I want to reassure people that the little girl is now getting the best possible care and treatment for her injuries at Alder Hey Children's Hospital.
"An extensive investigation is under way to establish exactly what has happened and to determine how many dogs were involved in the incident and the breed of dogs involved.
"I would appeal to anyone who was in the area at the time of the incident, who may have information which could help us with our investigation, to come forward as soon as possible."
A large police presence remained at the scene on Monday, with forensic officers in white boiler suits seen going to and from the house.
Anyone with information concerning the incident can call detectives on 0151 777 4065, or Crimestoppers anonymously on 0800 555 111.