One person killed during knife attack in Australian city of Melbourne

The attacker is in a critical condition under guard in hospital

One person killed during knife attack in Australian city of Melbourne

Chief police commissioner Graham Ashton address the media in Melbourne | Image via @VictoriaPolice on Twitter

Australian police have said they are treating a knife attack in Melbourne as terrorism.

One person was stabbed to death and two others wounded in the incident in the city centre.

Australian police said officers shot the man, who is under arrest and in a critical condition under guard at a hospital.

Chief Commissioner Graham Ashton said the suspect had also been known to Australia's security agency.

"We now know a bit more about the identity of that person - initially that person didn't have any identification on them.

"But we believe we now have confirmation on the identity of that person."

"He is known to police - and he's known to police mainly in respect to relatives that he has that are certainly persons of interest to us.

"And he's someone that accordingly is known to both Victoria Police and the the federal intelligence authorities".

The car was also full of "barbeque-style" gas bottles, Commissioner Ashton said.

Police were called to an incident on Bourke Street in the city at about 4.20pm local time.

Witnesses said the man had parked a vehicle there before setting it alight.

A man was arrested at the scene and has been taken to hospital under police guard in a critical condition.

Two people, apparently members of the public, came to the aid of police, one using a shopping trolley and another using a chair to try and stop the attacker.

This image made from video shows police on street corner after a shooting in Melbourne, Australia | Image: AP/Press Association Images

Social media footage showed the attacker trying several times to stab one of the officers, before a second officer drew his gun and a single shot could be heard.

Superintendent David Clayton from the Victoria Police earlier said: "Nearby police quickly responded to the incident - as they got out of the car, they were confronted by a male brandishing a knife and threatening them.

"At the same time, passers-by were calling out that members of the public had been stabbed.

"Police shot the male in the chest, and he's now in a critical condition under guard at hospital.

"Three people have been stabbed, unfortunately one is deceased at the scene - two other victims are currently in hospital."

"Police are not looking for any other offenders at this stage." Police earlier said there was "no known link to terrorism".

They are asking members of the public who have images or video footage of the incident to upload them online.

Additional reporting: IRN