Breaking: Child dead in alleged Sydney stabbing, two other children and woman critical - ABC News & Headlines – Australian Broadcasting Corporation

NSW Police say all the children in the alleged stabbing are under the age of five. (ABC News)

A child has died and two other children, and a woman, are in a critical condition after a stabbing in the Blue Mountains.

Police said all the children were under the age of five and the woman was in her 40s, but their identities are yet to be confirmed.

Just before 1pm today, emergency services received reports of three children and a woman in a vehicle with stab wounds on Waratah Road at Valley Heights, near Springwood, in the Blue Mountains local government area.

"One of the children was located deceased in the vehicle," NSW Police said in a statement.

"NSW Ambulance paramedics treated the two children and the woman at the scene before they were conveyed to Westmead Hospital and Westmead Children's Hospital."

Police say one of the children was found dead inside a car. (ABC News)

Several members of the public were rendering first aid as emergency services were being contacted.

A crime scene has been set up, with police saying they were not looking for anyone else in relation to the incident.

Anyone who was in the area at the time, has information or dashcam video is urged to call police or Crime Stoppers.