A one-year-old boy has died in hospital after being attacked by a Rottweiler in the yard of his grandparents' home, West Yorkshire Police said.

The dog, a family pet, snatched the boy from the arms of a 7-year-old girl who was carrying him at the Wakefield home on Friday afternoon.

The girl had gone to the kitchen door to stroke the animal, which was kept in the yard outside. When the door was opened the dog, without warning, grabbed the boy and carried him into the yard. The boy suffered serious injuries and was taken to Pinderfields General Infirmary but died later in the evening.

Armed police officers killed the dog, a two-and-a-half year-old female, at the scene. The family had owned the dog for about six months, which had not previously shown any signs of aggression, police said.

The boy had been staying with his grandparents for the Christmas holidays.

At the time of the attack the boy's parents were out nearby and he was being looked after by his 16-year-old aunt, together with the 7-year-old girl and another girl, aged 6. The aunt, who had been upstairs, was unable to rescue her nephew, despite striking the dog, and called emergency services, who found the boy lying seriously injured in the yard.

“Our thoughts go out to the family at this tragic time,” said Detective Superintendent Steve Payne.

“They are understandably devastated by what has happened and are being supported by specially trained officers.”

The attack came almost a year after 5-year-old Ellie Lawrenson was mauled to death by a family pit-bull terrier at her grandmother's house on January 1.

Her uncle Kiel Simpson was jailed for eight weeks for owning a banned breed of dog. Rottweilers are not banned by the Dangerous Dogs Act, but the legislation covers any dog out of control in a public place.