Two girls - both aged five - and an 11-year-old boy have died following a house fire in Singleton in the NSW Hunter Valley, police say.
Authorities are investigating whether a lit fireplace contributed to a blaze that ripped through a family home in the NSW Hunter Valley killing three children, despite the brave efforts of neighbours.
Emergency crews found the house on Brittcliffe Close in Singleton engulfed in flames about 3.30am on Wednesday following several calls to triple zero.
Two girls - both aged five - were rescued by firefighters and rushed to Singleton Hospital but died soon after.
An 11-year-old boy was later found dead inside the home.
"The house was well engulfed by fire at that time," a NSW police spokesman said. "What I can say is that in the efforts of trying to put the fire out, four residents have assisted and removed the mother - a 31-year-old lady, and an eight-year-old daughter from the house, safely.
"Two 5-year-old girls were removed from the house by Fire and Rescue staff.
"And subsequently taken to Singleton Hospital. Tragically, they were pronounced dead at Singleton Hospital."
The spokesman said that subsequent investigations revealed a deceased 11-year-old boy inside the house.
"We're working under the assumption at this time, whilst identities haven't been confirmed all of the children were occupants of that house," he said.
He said that the mother and an eight-year-old child are at the John Hunter Hospital receiving treatment for burns for the mother, and smoke-inhalation for the eight-year-old child.
"I would like to emphasise the heroic nature of the four residents in the nearby vicinity who tried to assist the people inside the house, and importantly, got the mother and eight-year-old daughter out and we're working with our welfare management to look after the welfare of all of the emergency service people who were involved in today's tragic incident," the police spokesman said.
Early investigations suggest the fire started at the front of the house before spreading to the back of the home.
Fire and Rescue NSW Superintendent Joshua Turner confirmed there was a fireplace in the house, but it was too early to say if it caused the fire.
"The fireplace is one of the factors that will be looked at to see if it was a factor, or if it can be eliminated," he said.
"But obviously during these winter months, heating appliances are quite prominent in fire causes."
Smoke detectors were installed in the home and could be heard by neighbours and emergency crews.
"With the intensity of the fire ... the neighbours and those that attended and tried to assist did a pretty incredible job," Supt Turner said.
Neighbour Brock Forbes said he and his family were woken up by a "big bang" and tried to fight the blaze until fire crews arrived.
"(We heard) just smashing and screaming so we ran out and grabbed the hose," he told the ABC.
"I was trying to put the fire out and trying to save them and firefighters came and got it under control."
Another neighbour said she also heard screaming coming from the property.
"I was woken up by screams and came out the front and the house was on fire," she told Nine's Today Show.
"There's so many children inside. It's just a shocking thing to happen to anybody."
Footage shows the house entirely engulfed in flames and part of the roof collapse.
ABC News has reported there were five people in the home at the time of the fire.
"At about 3.30am when it broke out, ambulances rushed two twin girls to hospital, but they died shortly after they arrived," the ABC's local reporter said.