A man has been arrested over a house fire that killed three young children in Sydney's west.
Emergency services were called to a home in Lalor Park at 1am on Sunday.
Two boys, aged two and four, were taken to Westmead Hospital in a critical condition, but they died a short time later.
Fire and Rescue NSW extinguished the fire before the body of a third child, believed to be a 10-month-old girl, was found.
The three children are yet to be formally identified.
Five other children, aged between six and eleven, were treated at the scene and taken to Westmead Hospital in stable condition.
A 29-year-old woman has been taken to hospital for smoke inhalation.
Police arrested a 28-year-old man at the scene.
He was treated for smoke inhalation and taken to hospital under police guard.
The cause of the fire is not yet known and a report will be prepared for the coroner.