A 32-year-old man arrested after a car slammed into multiple pedestrians in central Melbourne has been released from hospital into police custody.

Police say Heidelberg West man Saeed Noori, an Australian citizen of Afghan descent, was transported to the Melbourne Custody Centre on Friday afternoon and is expected to be “interviewed at a later time”.

Mr Noori is accused of intentionally driving a four-wheel drive into a crowd of pedestrians outside the Flinders Street train station.

The incident just after 4.40pm on Thursday left 18 people hospitalised, including a four-year-old boy.

Four people have since been discharged, but 14 remain in hospital, with three in a critical condition, including an 83-year-old man.

Nine of the victims are overseas nationals from countries including South Korea, China, Italy, India, Venezuela, Ireland and New Zealand.

According to The Australian, three of those injured were part of a family of seven visiting Melbourne from South Korea, including two men aged 61 and 67 and the four-year-old boy, who is one of the men’s grandsons.

Mr Noori was apprehended by an off-duty police officer shortly after the vehicle he was driving crashed.

Video just in: Accused Flinders Street attacker Saeed Noori in police custody after being released from hospital. Latest on 7 News at 6.00pm #7News pic.twitter.com/2MOUkvMU6p

— 7NEWS Melbourne (@7NewsMelbourne) December 22, 2017

Authorities in Melbourne have said they do not believe there is an increased threat to the public, and that Mr Noori had a history of drug use and mental illness.

Police said Mr Noori had made “utterances” during preliminary discussions with investigators, referring to the “mistreatment of Muslims” and “dreams and voices”.

Acting Chief Commissioner Shane Patton said Mr Noori made comments about Allah and ASIO from his hospital bed.

“I think there was something, and I don’t know the exact detail, to do with Allah and some ramblings about ASIO [the Australian Security Intelligence Organisation],” he told media on Friday.

However, they say he has no known terrorist links and there was no evidence he had planned his actions.

Mr Noori’s release from hospital comes after calls for “failures” in the mental health treatment system to be addressed to avoid further violent episodes.

“Clearly for Melbourne, it’s the second issue of its kind within 12 months, it has rocked us all to our core,” Victorian Opposition Leader Matthew Guy

“And if this is, as the police are saying, an issue related to mental health then we need to get to the bottom of what are those possible systemic failures in the system and we need to address them, not just say we’ll address them.”

Former Australian of The Year Patrick McGorry echoed Mr Guy’s concerns.

Professor McGorry said the shortcomings of the state’s mental health crisis sometimes resulted in violent episodes.

“We’ve seen a series of these sort of events, a man released from a psychiatric unit, again a mentally ill refugee who tried to hijack a plane, a woman who killed her children having inadequate psychiatric care, and probably the Bourke Street person is mentally ill and untreated and complicated again by drug use,” he told AAP on Friday.

On Friday night, a teenage man told Channel Nine news of his heroic efforts to save his friend from the out-of-control driver.

Ethan Caruso, aged 17, pushed his friend, Andre, 5, out of the path of the oncoming vehicle, getting sideswiped by the car in the process and sustaining torn muscles as a result.

“When he hit me, my legs just went straight up and I sort of just got launched into the air, because of the force, and ended up hitting my ankle and flew a few metres,” Ethan told the Nine Network.

– with ABC/AAP