SYDNEY -- Six people were killed in a knife attack at a shopping center in Australia's Sydney on Saturday and the attacker was shot dead by police, police said.

It has been confirmed the man fatally stabbed six people in the Westfield Bondi Junction shopping center before he was shot, New South Wales (NSW) Police said in a media advisory.

The attacker had been in the shopping center, left, and returned with a knife for his stabbing spree, NSW Police Assistant Commissioner Anthony Cooke told a press conference earlier.

"As he moved to the center, he engaged with about nine people, and it's clear that during that engagement he caused harm to those people. We believe by stabbing them with a weapon he was carrying," he said.

Cooke said the attacker was shot dead by a nearby police officer who was on her own.

"She confronted the offender who had moved by this stage to level five (of the mall) as she continued to walk quickly behind him to catch up with him," Cooke said. "He turned, faced her, raised a knife. She discharged a firearm and that person is now deceased."

The assistant commissioner said preliminary investigations suggest the man acted alone and that no motive is clear.

Asked by a reporter if police were ruling out terrorism, Cooke said, "We're not ruling anything out."

In a media conference Saturday evening, Australian Prime Minister Anthony Albanese said the attack was "a horrific act of violence" and offered his condolences.

"This was a horrific act of violence indiscriminately targeted at innocent people going about an ordinary Saturday, doing their shopping," Albanese said.

"Our nation offers our deepest condolences and sympathies to all those who are grieving for someone they have lost and we send our strength to those who have been injured," he said.