Here's what we learned from NSW Police Commissioner Mal Lanyon in the earlier press conference.
"As a result of the circumstances of the incident tonight, at 9.36pm this evening, I declared this to be a terrorist incident."
Lanyon said he had authorised "special powers" within Australian law to "ensure if there is a third offender - and we are currently investigating that at the moment - we will make sure that we prevent any further activity".
He was asked by reporters why police believed there could be a third person involved.
"I cannot confirm there is a third offender, but I want to make sure there's no stone left unturned," he responded.
"Part of the [terrorism] declaration is because I have information about the deceased shooter, [but] it's not something I am prepared to [share] at the moment."
The police counter terrorism unit would lead a significant investigation into the incident, Lanyon said.
"This type of disgraceful activity, this wanton use of violence, the taking of innocent lives, is unacceptable to New South Wales. It's not our way of life."
Lanyon asked for calm in the community so the the police could do its job: "This is a time where I want to make sure there is no retribution."
There had been a "massive police response" to the incident.
"I'm incredibly proud of the professionalism of our police and emergency services responders, they have done a fantastic job."