Police have said a crash in Australia which injured 14 people, some seriously, was a "deliberate act".
The incident outside Flinders Street station in Melbourne occurred at around 5pm local time (6am GMT) on Thursday evening.
Images from the scene showed a number of people receiving medical attention, while a white Suzuki SUV appeared to have collided with a phone box.
Victoria Police tweeted that officers were "currently attending an incident on Flinders Street between Elizabeth and Swanston streets where a vehicle has collided with a number of pedestrians.
"Police have arrested the driver of the car. Extent of injuries are not known at this stage."
Ambulance Victoria tweeted: "Paramedics have now transported 13 people to city hospitals. Two more people are being assessed by paramedics at the scene."
Police later said a second man had been arrested.
The force said: "Police have saturated the CBD (central business district) area following an incident where a car has collided with a number of pedestrians on Flinders Street.
"The incident occurred when the vehicle struck a number of pedestrians in front of Flinders Street Station just after 4.30pm.
"The driver of the vehicle and a second man have been arrested and are in police custody.
"A number of people were treated at the scene for a range of injuries and have been transported to hospital."
A woman called Sue told 3AW radio: "As it (the car) approached this intersection... it just mowed everybody down, people were flying everywhere."
And man who was working in a nearby shop, and was at the scene before emergency services arrived, told the Australian Associated Press: "There was no screaming, just people lying there."
Vince added that onlookers were "just holding them and comforting them".
Kyra Gillespie was one of "hundreds of people" who were told to get off trams near the area following the incident.
She told ABC News: "I think everyone is a little bit shaken up by the experience.
"Lots of people were phoning their loved ones to tell them they were OK."
Leader of the opposition Bill Shorten tweeted: "Shocking scenes in Melbourne this afternoon. Credit to first responders who are doing us proud once again. Thinking of everyone caught up in this atrocity."
Social media images from the scene showed casualties being treated in the street by paramedics.
A young man in jeans and a teeshirt could also be seen being arrested by three police officers on the steps of the station, although it was unclear if he had been in the car.
According to the AAP, a witness said the Suzuki was travelling at around 60mph.
"The intersection was full of pedestrians and he just ploughed through," the witness named Jim told ABC TV.
"The only thing that slowed him down was him hitting pedestrians.
"There was no braking, there was no slowing down. Whether it was targeted or whether he had a heart attack, or was drunk, I don't know."
Sky News said the driver of the SUV was of Middle Eastern appearance and that he was wrestled to the ground and handcuffed following the crash.
Lachlan Read told the Herald Sun the whole incident lasted about 15 seconds.
"It was bang, bang, bang. It was just one after the other.
"The last bang the car stopped," the 20-year-old said. "There were bodies on the ground and people running up to them - it was mayhem.
"It is definitely something you don't expect to see on Flinders Street."
It was the first week of school summer holidays in Victoria, and the area was busy with Christmas shoppers.
Elton Hindoli, who works at an off licence by the scene of the incident in Elizabeth St, told the Herald Sun that a man who was pulled from the car appeared to be unconscious.
"A girl came into the shop and she was very upset," he said.
"She said a guy in a big car had hit about six people.
"It wasn't clear if the driver was hitting them on purpose or not.
"He hit the people then crashed into the tram area in the middle of the road."
A man who was working in a nearby shop and was at the scene before emergency services arrived told the Australian Associated Press: "There was no screaming, just people lying there."
Victoria Police said officers had "saturated" the city's central business district following an incident where a car had collided with a number of pedestrians on Flinders Street.
"The driver of the vehicle and a second man have been arrested and are in police custody," the force said.
"A number of people were treated at the scene for a range of injuries and have been transported to hospital.
"A crime scene has been established and all vehicular and pedestrian traffic are advised to avoid the area."