Two eight-year-old boys have been killed and 17 of their classmates are injured after a car crashed into their classroom.
The SUV careered through the wooden walls of Sydney's Banksia Road Public School not long after lessons started on Tuesday.
Ambulance service superintendent Stephanie Radnidge said medics arrived to "a scene of carnage".
She told reporters: "There were a number of distressed and overwhelmed children and teachers at the scene of a horrible accident.
"Obviously they were crying, they were distressed, some were asking for their parents, that's a natural response in such a terrible set of circumstances.
"There was obviously pandemonium."
One distraught father described lifting the car off a dying boy while another child screamed for his mother in the chaos after the crash.
"Three of us lifted it and one of the blokes grabbed him out from underneath," a witness told Sydney's Daily Telegraph.
"He was saying 'I want my mum'. She wouldn't have got to see him before he died."
Student Mariam Issmail told the Australian Broadcasting Corporation she saw a teacher faint after the crash, while others helped children into ambulances.
"They were all just covered with blood. It was very bad," she said.
Five children were taken to Sydney's Westmead Hospital, including the two boys who died.
Three girls - including a nine-year-old and two-eight-year-olds - are in a serious condition.
Police said 17 children and a teacher were treated at the scene for minor injuries.
The crash is being treated as an accident.
The 52-year-old woman driver was taken away for questioning and for alcohol and drug testing.
She has since been charged with dangerous and negligent driving.