Suspect in Australian car ramming 'spoke about voices': Authorities The driver was arrested at the scene.

 -- The suspect who plowed a vehicle into a crowd of pedestrians in Australia on Thursday spoke to investigators while in the hospital after being detained, authorities said.

"He spoke about dreams. He spoke about voices. But he also did attribute some of his actions to the poor treatment of Muslims," Victoria Deputy Commissioner Shane Patton said on 9News' "Today" show on Friday morning local time.

The suspect's name has not been released, but he has been identified as a 32-year-old male who is Australian of Afghan descent. He was arrested on the scene and was injured in the ramming. Police said 19 people were injured in the ramming, including the perpetrator and an off-duty police officer.

The suspect was released from the hospital into police custody.

When asked if there is a link to terrorism, Patton told 9News, "That's certainly what — one aspect we're exploring in respect to the motivation."

The suspect had a mental health appointment scheduled for Thursday before the ramming, but he missed the appointment, Patton said, adding that the suspect still needs to undergo a psychiatric assessment and be formally interviewed.

Police earlier said that the suspect, who was driving a white Suzuki SUV that was used in the ramming, has a history of drug abuse and mental health issues.

Authorities said the ramming, which occurred just after 4:30 p.m. local time, was a "deliberate act" but repeatedly said they do not yet know the motivation.

Of the 18 people taken to the hospital, 14 are still being treated, and three people are in critical condition.

Nine of the victims are from overseas, including three from South Korea, and one each from China, Italy, India, Venezuela, Ireland and New Zealand. No Americans were injured.

9News in Australia reported a 4-year-old girl was among those taken to the hospital with a serious head injury.

A second person detained Thursday near the site of the ramming was released, according to police. It was determined that he was not linked to the ramming, police said. However, the man was charged with possessing cannabis and a controlled weapon, police said. Police said earlier in the day three knives were found in his bag when detained.

All roads near the site of the ramming have been reopened to the public.

The area where the ramming occurred was filled with pedestrians and people doing holiday shopping.

"This is horrific. It's evil," Victoria Premier Daniel Andrews said. "We are not defined by these sorts of incidents."

Paul Calahane, a native of Ireland who said he has been in Melbourne for seven weeks, was returning home from work when the ramming unfolded behind him.

"I heard a bit of a bang behind me, even though I had my headphones in with a bit of audio," Calahane told ABC News. "I leaned forward, thinking it was a blast, then I saw people running. I saw people just scattered on the road ... There were people running, screaming, thinking it was a bomb."

Calahane said he turned to see across the street the white SUV, which had plowed into a light pole. He said a man was pulled out of the vehicle and arrested.

"Within a minute, there was about 40, 50 people on the scene," he said. "They were really pushing people back from the scene."

A man named Jim, the owner of a bakery across the street, told the Australian Broadcasting Corp. he saw many people hit.

"He came to rest just next to the tram stop -- maybe the side of the tram stop stopped him -- but the only thing that seemed to be slowing him down was the amount of pedestrians he had hit," the man said. "All you could hear was just bang, bang, bang, bang, bang."

Police said at a Thursday evening press conference that security would be stepped up in the area and that the investigation scene would be in place for a considerable amount of time.

"It sounded as though there could be a bomb, but then people who were there came running into the station saying that a vehicle had plowed through pedestrians," a woman named Nicola told the Australian Broadcasting Corp. "And another lady was hysterical because, like all of us, it could have been us."

Police said "a number of people were treated at the scene for a range of injuries and have been transported to hospital."

Transit authorities notified riders that routes through the area were being altered.

But Andrews expressed confidence that residents will carry on. "I'm confident that we will go about our business and we will celebrate Christmas," he said.

He added, though, "We will all, I think, spare a thought for those that have been touched and, indeed, forever changed by the evil and cowardly scenes on Flinders Street today."

Six people were killed in a vehicle ramming in Melbourne in January. The driver plowed into crowded Bourke Street, just a few blocks north of Flinders Street, where Thursday's ramming occurred. The man was charged with six counts of murder and has pleaded not guilty. Officials did not charge him with terrorism offenses, and his lawyer said he has mental health issues, according to the Australian Broadcasting Corp.

This is a developing story. Please check back for updates.

ABC News' Matt Foster, Rex Sakamoto and Briana Montalvo contributed to this report.