Transcript for 'Deliberate' car ramming injures 19 in Australia

A terrifying attack in Australia. A driver rammed into a crowd of holiday shoppers during rush hour on a busy street in Melbourne injuring more than a dozen people. Police have called it deliberate and that driver is under arrest along with another person and James Longman has the latest. Good morning. Reporter: Amy, good morning. Police are saying they still have no clear idea on motive, although the suspect's mental health issues are being raised. This is another deadly attack in a major western city. The white SUV plowed through crowds as they crossed this busy street barreling across an intersection filled with pedestrians. 19 injured, several in critical condition. A preage school rushed to the hospital with a head wound. At this stage we believe it's a deliberate act. Reporter: Witnesses say the SUV ran through red lights, railed onto rail tracks before deliberately taking aim at those going about their day. Turned around. People scattered and rolled. Some were nonresponsive. He made a collision with the people but obviously a pole or curb and lost control of the vehicle and crashed. I saw a man getting arrested outside of the jeep, maybe 30 years old. Reporter: They say the perpetrator has a history of mental illness. One witness posting this. This is the man would rammed into pedestrians. There was one sole person in the car that was the driver. That's the offender we have in custody and there was also another 24-year-old male in close proximity around that time filming that incident with his mobile phone and had a bag with possession of knives in it and taken into custody to determine whether he was in fact connected with the incident. At this stage we don't believe that to be the case. Scary, obviously. Reporter: The area still on lockdown. I heard what I thought was shots through the crowd. Reporter: A similar incident took place just around the corner from here in January. That killed six people. As a result concrete blocks were installed to prevent these car attacks but didn't manage to stop this. Thanks so much. ABC news's Aaron katersky joins us from Australia.

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