The driver who rammed his car into Melbourne pedestrians is a 32-year-old Australian citizen of Afghan descent with a history of drug use and mental health issues. Police say there is no evidence that it was an act of terrorism.

Speaking at a press conference, Melbourne authorities said the driver was "known to police" and remains in custody. However, they said they "don't at this time have any evidence or intelligence to indicate a connection with terrorism."

READ MORE: 19 people injured as car 'deliberately' hits pedestrians in Melbourne

A 24-year-old male was also arrested at the scene after he was seen to be filming the incident with his mobile phone. He was searched by police and found to have three knives in his possession. He is still being interviewed by police, though authorities say they do not believe he was connected to the incident.

Dramatic moment of Melbourne suspect's arrest and the immediate aftermath pic.twitter.com/MxMA24qfXG — Ruptly (@Ruptly) December 21, 2017

A total of 19 people were injured in the car ramming. Of those, 15 are in stable condition and four are critical. The driver is one of those patients.

Authorities say they are treating it as a "singular incident" and have encouraged Melbourne residents to continue their lives as usual. Hundreds of police will be deployed throughout the city to provide "increased reassurance," although authorities added there is "no increased threat."

The incident occurred in front of Flinders Street Station at around 4:30pm local time on Thursday. Shortly after the attack, authorities issued an appeal for photos and videos which "might assist police with their investigation."