Updated at 6:35 a.m. ET
An SUV plowed through a group of pedestrians during rush hour Thursday in the city of Melbourne, injuring at least 14 people, in what police say they believe was a "deliberate act."
Two people are in custody following the incident at the intersection of Elizabeth and Swanston streets, near Flinders train station at about 4:45 p.m. local time in the southern Australian city of nearly 4 million people.
Victoria Police Commander Russell Barrett told reporters that 14 people had been injured and that several of them are in critical condition.
"At this stage we believe it was a deliberate act, but we don't yet know the motivation," he said.
The car came to a halt after hitting what The Sydney Morning Herald describes as a "metal bollard."
The newspaper, which identified the vehicle as a Suzuki Vitara, says bystanders "stepped in to restrain one of the men in the car."
When pressed on details of the two people arrested or on whether terrorism was being ruled out as a possible motive, Barrett declined to elaborate, saying only that "it's too early in the investigation" to provide such information.
Later, Melbourne police said they had no immediate evidence to suggest it was terrorism-related.
NPR's Rob Schmitz reports that the vehicle appeared to have run a red light before striking the pedestrians.
"I saw a car, a SUV coming at high speed and really just heard the collision with people with bags and what must be shopping trolleys — and I hope not prams," a witness identified only as John was quoted by the Australian Broadcasting Corporation.
He said the vehicle was traveling "at high speed," ABC says.
A preschool-aged child is among those injured, sustaining a serious head injury, the Herald says.
The newspaper reports that "Up to seven have been taken to hospital ... Officers are holding up tarps around some victims."
Sue, another witness, who was working at a nearby doughnut shop, was quoted by local 3AW radio as saying she heard screams before she saw "people flying everywhere." "We could hear this noise, as we looked left, we saw this white car, it just mowed everybody down," she told the radio station. "We heard thump, thump. People are running everywhere."
Thursday's incident took place near the location of a January vehicle attack in which four people were killed and about 20 injured. The driver was reportedly fleeing police after stabbing his brother and it was not deemed a terrorist attack.