Fifth person dies after Melbourne car attack

Australian police said on Sunday a baby boy has become the fifth person to die after a 26-year-old man drove a car into a crowd of pedestrians on a busy street in Melbourne.

The three-month-old died two days after the incident, which also left another 20 people seriously injured, as police wait to question the driver who was hospitalized after being shot by officers attempting to stop the carnage.

Police have said the incident was not related to terrorism, dispelling initial fears that it might have been a militant attack.

The police rammed his car and the driver was shot in the arm before being dragged from the vehicle.

The bullet wound to the arm was not life threatening, but needed surgery, Victorian police commissioner Graham Ashton told reporters in Melbourne on Saturday.

"That surgery is still occurring," Ashton said. "Through the course of the weekend we will be looking to try and get that opportunity to step in and interview and charge that offender."

A 10-year-old girl, 25-year-old man, 33-year-old man and 32-year-old woman were also killed in the incident, but police said the death toll could rise as four others were very seriously hurt.

Hospitals have treated 37 people in total following the rampage.

Ashton said the incident was not terrorism related, and that the driver had a "criminal history" that included domestic violence charges laid a week earlier for which he was already on bail.

Victorian Premier Daniel Andrews said a memorial would be built to the victims in the Bourke Street mall where they died. He joined dozens of others in laying flowers at a makeshift shrine on the footpath there.