* Bishop Mar Mari Emmanuel, 53, was delivering a sermon at Christ the Good Shepherd Church in Sydney's west on Monday night when a person stabbed him in the head

* Another clergyman, 39, was injured when he tried to intervene, suffering a wounded shoulder and lacerations

* Both men had non-life threatening injuries and were taken by ambulance to Liverpool Hospital

* The sermon and attack were live streamed with footage appearing to show a person in black stepping up to an alter and attacking Bishop Emmanuel with a flick knife

* A 16-year-old was restrained by witnesses and later arrested by police

* He has since had surgery and is under police guard

STREET VIOLENCE

* Hundreds of people gathered outside the church following the stabbing

* Police arrived to respond to the stabbing and the crowd "turned" on them, NSW Police commissioner Commissioner Karen Webb said

* Two officers were injured as bricks, concrete and palings were used to assault police while 20 vehicles were damaged, Commissioner Webb said

* The force said one constable suffered a broken jaw and another suffered a chipped tooth and twisted knee

* Seven people were taken to hospital and paramedics checked about 30 people, with about 20 being treated for the effects of OC spray

* Several houses nearby were broken into, according to NSW Police Acting Assistant Commissioner Andrew Holland

STABBING MOTIVATION

* The stabbing was declared a terrorist attack about 1am on Tuesday

* Commissioner Webb said the teen made comments indicating the attack was religiously motivated

* She said police allege the attack had "a degree of premeditation" and the teen was known to police but not on a terror watchlist

* ASIO Director-General of Security Mike Burgess said there is no indication others were involved in the stabbing and no other threats of similar incidents

* Prime Minister Anthony Albanese urged people not to speculate on the motivation

AFTERMATH

* Political and religious leaders have urged people not to launch retaliatory attacks

KEY QUOTES - STABBING

"We believe there are elements that are satisfied in terms of religious motivated extremism and of course, the intimidation of the public through that person to act by attending that church while it was being live streamed" - NSW Police Commissioner Karen Webb

"It does appear to be religiously motivated, but we continue our lines of investigation" - ASIO Director-General of Security Mike Burgess

"I understand that people are feeling uneasy, and that is understandable, given the atrocities that occurred on Saturday and then this incident last night" - Prime Minister Anthony Albanese

KEY QUOTES - STREET VIOLENCE

"Police attended the incident in Wakeley to assist that community in response to calls for assistance and the crowd turned on police. That is unacceptable and those that were involved in that riot can expect a knock at the door" - Commissioner Webb

"No one is asking for retribution or to take the law into their own hands, it's my great plea that everybody in Sydney to heed those calls from New South Wales please, the government and major religious leaders" - NSW Premier Chris Minns

Australian Associated Press