Police have addressed the media following an incident in Melbourne just after 4.30pm today.
A vehicle collided with pedestrians in the Melbourne CBD near Flinders Street Station, with numerous people injured.
Police have said that 14 people are being treated and several are in a critical condition.
"We believe it is a deliberate act," a police spokesperson said.
People are encouraged to avoid the area as a crime scene will be in place for a considerable time.
The motivation is currently unknown.
A vehicle has rammed into pedestrians near Flinders Street Station, with more than 13 people taken to hospital.
Two more are being assessed at the scene.
The driver of the car has been arrested, along with another man.
Police have cordoned off a large area as investigations commence.
Witness reports describe the traumatic incident, with some observing the speed at which the vehicle collided with pedestrians.
"He seemed to be travelling at 80 to 100km/hour in a western direction," a witness said.
"The only thing that slowed him down was hitting people."