NSW Police have reportedly shot a knife-wielding man at Westfield Hornsby in Sydney.
Police sources have told 9NEWS an offender was ranting and approached police with a knife.
Witnesses claimed the man had been screaming and shouting at the officers, before he was shot.
NSW Police confirmed officers are responding to an incident at the Westfield mall in Hornsby.
"As a consequence four people have sustained various injuries and have been taken to hospital," the statement said.
"At this stage it is not known what caused the confrontation."
NSW Ambulance says it has responded to multiple injuries and have multiple units at the site.
Workers in the area told of hearing shots being fired.
Magdy Abdalla from the Java Lava Cafe on Florence St told AAP he heard gunshots and immediately fell to the floor.
"I told all of the customers just stay on the floor," he said.
"I was scared. I just heard the shooting. I saw some people running and I just had a look. I found three older ladies on the floor bleeding, one injured in the leg, one in the arm and the other one maybe in the back."
Mr Abdalla also reported seeing a young, skinny man, aged in his early 20s, lying on the ground.
"Police officers came in one minute."
The shooting is believed to have happened near the water clock, outside a on Florence Street before midday.
The man was shot in the stomach and arm, Channel Nine said, and three female bystanders suffered leg injuries.
Witnesses took to social media to report hearing gunshots and seeing the man and three other people on the ground.
