Caerphilly MP Wayne David told Wales Online: “Naturally I’m extremely saddened and upset at what’s happened. It must be appalling for the family.
“It’s important that the community pulls together and works closely with police.
“It’s difficult to speculate at this time – the circumstances that have happened, we need to learn lessons going forward.”
Local councillor Lindsay Geoffrey Whittle said: “The entire community is in total shock at such a terribly devastating incident.
“We are all thinking of their loved ones. It’s absolutely tragic, heart-breaking.”
One nearby resident, who asked not to be named, said: “He was a lovely boy and so harmless. It’s just so sad. He was so young.”
A nearby resident told the PA news agency: “The dog has been a nuisance on the estate for a bit of a time. I took our son down to the local shop a few days ago, and he was down there then and he was lunging at my son.
“My son is three years old and I had to pick up my son just to move around the dog because of the size on him. He was absolutely huge.
“He wasn’t a pet – he was taking the owner for a walk, you know. He was massive.”
Officers urged anyone with information to call 101, quoting log reference 2100392510.