Police have praised the extraordinary bravery of bystanders who ran towards danger today, confronting a man armed with a knife in Sydney’s CBD and preventing potential tragedy.

An emergency situation unfolded near Wynyard Station at about 2pm when a man armed with a large knife allegedly stabbed a woman at a hotel on the corner of King and Clarence Streets.

The man, who appeared to be caucasian and aged in his 20s, fled on foot and attempted to stab “a number” of other people, police allege.

Police have also found the body of another woman in a nearby residential unit, with The Daily Telegraph reporting her throat was slit.

It was the selfless quick-thinking of several men who worked together to stop the alleged attacker that likely prevented further tragedy.

“Shoot me,” the man could be heard screaming as he raced eratically down the street. “Shoot me in the f***ing head. Shoot me! Allahu Akbar.”

Without hesitation, one man armed with nothing but a wicker chair from a nearby cafe slowly approached the alleged attacker.

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The alleged knifeman jumped onto the bonnet of a black Mercedes, which sped off and knocked him to the ground, as the bystander continued to approach.

“All of a sudden this guy appears with a knife in his hand, covered in blood on his shirt,” the driver of the vehicle told Channel 9.

“Next thing, I thought I obviously can’t go through all those cars and as I’m thinking about doing something the guy jumps on the front of the car … and gets up to the very top.

“I froze for a split second but then I thought I hope he’s not covered in explosives or anything and I quickly accelerated and veered to my left on Clarence Street.

“Then I made a right turn to get back onto York Street and there he was again being chased near York and Clarence, by the police and the public, by firies, with chairs and everything they could get their hands on.”

A New South Wales Fire and Rescue Service truck was in the area when the mayhem erupted and witnesses say a number of firemen leapt from it.

One gave chase with an axe while another appears to have grabbed a restaurant chair, witnesses say.

Three other bystanders joined in, one armed with a chair and another with a milk crate.

The group, who police have described as “heroes”, managed to bring the man to the ground and restrain him using their unlikely combination of items.

His body was pinned down with the two chairs and a milk crate until police arrived.

British-born recruitment consultant Luke O’Shaughnessy, a former Thai boxing champion, was one of those who gave chase and held down the milk crate on the man’s head.

He and colleagues — his brother Paul, Lee Cuthbert and Alex Roberts — from MAP Talent heard a commotion from inside their King Street office.

“We all kind of chased, worked together, but it was Luke who was the real hero,” Mr Cuthbert told Channel 9 newspapers. “He pursued him the hardest and managed to get a grip of him with another man. Luke is down at the police station giving a statement.”

Police Minister David Elliott said today’s events are shocking but Sydney can celebrate “three new heroes”, who had “acted well and truly beyond the call of any citizen”.

Mr Elliott also praised the fire fighters who gave chase, as well as police for their swift response.

“This could’ve been much worse if not for the response of the citizens, the firies and the police,” he said.

“This is how Sydneysiders respond. If you want to put lives at risk in this city, just beware that it’s not only the police who respond. It’s the citizens, the firies, the ambos and anyone else.

David Vaux was coming back from a quiet lunch break and the scene become so dramatic he thought a crime television show was being filmed.

“A man came around the corner carrying a knife and being chased by another five or six men,” he said.

“All of them were carrying crow bars or an axe and one was carrying a camera. I thought it was a scene from a television crime show but that quickly turned out not to be the case.”

Mr Vaux said the patrons at the cafe the man ran past quickly realised they needed to help apprehend the man, pinning him down.

“It was a matter of seconds, it all happened so fast. They guy couldn’t move at all. He was absolutely in a distressed state. He didn’t seem sound of mind at all.

“I think it was an extraordinary response by the public and it just demonstrates people are prepared to do the right thing if called upon.”

“A number of members of the public physically restrained the offender and I want to acknowledge those people,” NSW Police Superintendent Gavin Wood said.

“They were brave and I use that word seriously. They were significantly brave people. To approach a person with the mindset of what this person (had), these people are clearly heroes.

“These people, going about their day to day business, have jumped into a situation that’s extremely dangerous. They have brought a person, who stabbed an innocent person for no specific reason, into custody.”

The woman was rushed to St Vincent’s Hospital with a stab wound to her upper back and is in a stable condition.

A heavy police presence remains at multiple crime scenes. The man is in custody.