Image: Nine News

Three children have been killed in a house fire in the Hunter Valley overnight.

The alarm was raised just before 3.30am when the blaze took hold of a family’s home on Brittliffe Close at Singleton.

Police quickly arrived at the scene and tried to force their way into the burning home but were kept back by the intense heat.

Firefighters arrived shortly afterwards and began attacking the flames which had caused the roof to collapse, trapping several occupants.

Five-year-old twin girls were freed from the wreckage and rushed to Singleton Hospital where they were tragically pronounced dead on arrival.

An 11-year-old boy’s body was also found inside the house.

The family’s mother, a 31-year-old woman, and her eight-year-old daughter were also taken to hospital.

The woman is being treated for burns and her daughter is being treated for smoke inhalation.

Police have confirmed three children have died following a house fire at Singleton in the Hunter. A woman and a fourth child are in hospital. @2GB873

— Alice Hogg (@alicemhogg) June 25, 2019

Police have praised the “heroic nature” of four neighbours who desperately tried to put the fire out with a hose.

Superintendent Joshua Turner from Fire & Rescue NSW tells Ben Fordham the neighbours managed to get the mother and daughter out of the house.

“They were very lucky to actually get out and a lot of that can be attributed to work the neighbours did in this event.”

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Police and fire investigators will now begin examining how the fire started.

A GoFundMe page has been set up to help the family through this time.