text: The boy, named locally as Reggie, was attacked at a house in Falkland Road at about 04:15 BST.
  He was taken to hospital where he later died. Police said the small terrier dog had been removed from the address and was likely to be destroyed.
  Northumbria Police said a 30-year-old man had been arrested in connection with the incident.
  A family member, who did not want be identified, said the baby's mother - named locally as Maria Blacklin - was not in the house when the youngster was attacked.
  The man said the baby's mother never left her son alone with the dog and she was devastated by what had happened.
  A neighbour said the baby was a "lovely bairn".
  She said: "They're all right [the family], they're no bother and his wife, she looks after them bairns, she was over the moon with her little boy.
  "It's a shock more than anything else, I cannot get over it. It's shocking."
  Flowers have been laid against the front wall of the house, along with cards bearing messages of support.
  Superintendent Gillian Mitchell said: "As you can appreciate, we have concerns with regards to the care of the child at the time this incident occurred.
  "They [the family] are absolutely devastated as you would imagine, it's tragic to lose a child at any stage, but in these circumstances it is just unbelievable.
  "They are receiving support... it is a very difficult time, the officers attending the scene this morning were faced with quite a significant incident to deal with.
  "It's a tragic isolated incident and our thoughts are with the family and friends of the baby and indeed our officers who have dealt with this incident."
  Police said additional officers were in the area to provide reassurance to support the public during an "horrendous time in the community".
  A police car remains parked directly outside the front of the property.
  Police said the family's dog posed no threat to the wider public and is now in secure kennels.
  More than 200,000 people a year are estimated to be bitten by dogs in England, according to research for the British Medical Journal.
  Since 2005, 22 people have been killed by dogs in the UK, 12 of them children, according to the Office for National Statistics.
  Everybody you speak to in this quiet tree-lined street knows the family of little Reggie.
  His proud mum had introduced him to their neighbours in recent days.
  They also knew the family had a dog, a small terrier which they believed had a good temperament. It obviously didn't.
  Those same neighbours have spent the afternoon leaving flowers outside the three week old baby's home - many of them in tears.
  "He was a bonny little lad", one of them remarked.
  A relative came by to tell us the terrier dog was usually kept in a brick outhouse at night. He couldn't understand why the dog was in the house. He also told us the dog was always well behaved around the other children in the home.
  The animal is now being kept in secure kennels while police continue their investigation. Meanwhile, a family is trying to come to terms with the loss of their new born child in such horrific circumstances.
target: A three-week-old baby boy has died after being bitten by a dog in Sunderland.