Four children have died in a fire that tore through a house in south-west Melbourne.
File pic Photo: AAP
Police said investigators were told the fire started at the house on Mantello Drive in Werribee shortly after 1am (local time).
Thick black smoke was seen pouring from the brick home.
The four children were all unaccounted for early on Sunday morning.
Police have now confirmed the two boys and two girls could not be saved in the blaze.
The 10-year-old and three-year-old boys and six-year-old and one-year-old girls were found deceased inside the home.
A man, a woman and their eight-year old child were taken to hospital with smoke-related injuries.
"It is a terrible set of circumstances, and one that's very difficult for the members of the family, and our hearts go out to the family and what's occurred here," said Detective Senior Sergeant Ashley Ryan.
"But also very distressing for members of Victoria police and the emergency services, given the circumstances."
It took about 40 firefighters just under an hour to bring the fire under control.
One firefighter was assessed for chest pain, authorities said.
The Victoria Police arson squad is now trying to piece together what caused the fire and where it started.
Police are unable to say whether it is being treated as suspicious at this stage.
Specialist fire investigators from the Country Fire Authority and Fire Rescue Victoria are working with arson squad detectives on the investigation.
"This is in particular very tragic circumstances with four young children that have perished in the fire," said CFA commander David Clancy.
Clancy said the fire had extended well throughout the house by the time he arrived to assist the crews.
"Firefighters had a fairly arduous task to undertake the fire fight and were unable to conduct an internal attack due to the heat of the fire," he said.
Counselling is being provided to the emergency crews who were on the scene.
-ABC