Community leaders are calling for calm after a teenager was accused of wounding a Christian bishop and priest during a church service in a second high-profile knife attack to rock Sydney in recent days.

The 16-year-old was overpowered by the shocked congregation at Christ the Good Shepherd Church after he allegedly stabbed Bishop Mar Mari Emmanuel and Fr Isaac Royel during a service on Monday that was being streamed online.

Police have not commented on reports that the boy’s fingers were severed by parishioners in the Orthodox Assyrian church in suburban Wakeley, but confirmed his hand injuries were “severe”.

Video of the attack spread quickly on social media and an angry mob converged on the church demanding vengeance.

They hurled bricks, bottles and fence boards at police, who temporarily barricaded the boy inside the church for his own safety. Many in the crowd chanted “an eye for an eye” and “bring him out”.

Several people including police officers required hospital treatment following the hours-long riot.

The church said in a statement on Tuesday it “denounced retaliation of any kind”.

Police stood guard around mosques in parts of Sydney on Tuesday after reports that text messages were circulating urging the Assyrian Christian community to retaliate against Muslims.

Police and community leaders said public anxiety had been heightened by a lone assailant’s knife attack in a Sydney shopping mall on Saturday that killed five women and a male security guard who attempted to intervene.

The 40-year-old assailant, Joel Cauchi, had a history of mental illness and trouble with women and a fascination with knives. He was shot dead by police.

Prime Minister Anthony Albanese urged the public not to take the law into their own hands.

“We understand the distress and concerns that are there in the community, particularly after the tragic event at Bondi Junction on Saturday,” Mr Albanese told reporters, referring to the Westfield Bondi Junction shopping mall.

“But it is not acceptable to impede police and injure police doing their duty or to damage police vehicles in a way that we saw last night,” he added.

News South Wales Police Commissioner Karen Webb on Tuesday declared the church attack a terrorist incident, but not the shopping mall rampage.

The terrorism categorisation allows more law enforcement resources to be focused on the crime. The declaration also gives police expanded powers to stop and search people, premises and vehicles without a warrant.

Ms Webb said the teenager’s comments and actions pointed to a religious motive for the attack. She did not detail the wording of the comments that led her to believe he had been religiously motivated.

Ten Network television reported the boy had told churchgoers who restrained him in Arabic: “If they didn’t insult my Prophet, I wouldn’t have come here.”

The Australian Security Intelligence Organisation (ASIO), the nation’s main domestic spy agency, and Australian Federal Police have joined state police in a counterterrorism task force to investigate who else was potentially involved.

ASIO director-general Mike Burgess agreed with Ms Webb that the mall attack was not terrorism as defined by Australian authorities.

To call it a terrorist attack, there must be “information or evidence that suggests actually the motivation was religiously motivated or ideologically motivated,” Mr Burgess said.

“In the case of Saturday, that was not the case. In this case, the information we and the police have before us … would indicate strongly that that is the case and that’s why it was called an act of terrorism.”

A coronial inquest will investigate the circumstances of the six knife deaths in the mall attack and what policy changes could be made to prevent similar attacks from occurring in the future.

The coroner will also consider whether security guards should be armed. Westfield Bondi Junction shopping centre guards, which included victim Faraz Tahir, do not carry guns.

New South Wales Premier Chris Minns said he was reviewing government restrictions on how security guards could be armed following the knife attack. But he has ruled out allowing them to carry guns, saying the fewer firearms in the community, the better.

Mr Minns said state police were urging social media platforms to shut down accounts posting misinformation that incited violence since Monday’s stabbing.

“New South Wales Police and community leaders have been battling misinformation spreading around the web inciting community members to rush to particular religious facilities and mosques and churches on the hint or the rumour of some kind of violent activity taking place,” Mr Minns told Australian Broadcasting Corp.

“It’s very difficult to maintain community cohesion when outright lies are spread within the community inciting the worst fears of particularly young people,” Mr Minns added.

The teenage suspect was in hospital on Tuesday under police guard. He has yet to be charged.

Ms Webb said the he had been known to police, but was not on a terror watch list.

He had been convicted in January for a range of offences including possession of a switchblade knife, being armed with a weapon with an intention to commit an indictable offence, stalking, intimidation and damaging property, Australian Broadcasting Corp reported.

A Sydney court released him on a good behaviour bond, ABC reported.

The boy used a switchblade, which is an illegal weapon in Australia, in Monday’s attack, ABC reported.

Juvenile offenders cannot be publicly identified in New South Wales.

The church in a message on social media said the bishop and priest were in stable condition and asked for people’s prayers. The church said in a statement on Tuesday the 53-year-old Iraq-born bishop’s condition was “improving”.

Bishop Emmanuel has a strong social media following and is outspoken on a range of issues. He proselytises to both Jews and Muslims and is critical of liberal Christian denominations. He also speaks out on global political issues and laments the plight of Palestinians in Gaza.

The bishop, described in local media as a sometimes divisive figure on issues such as Covid-19 restrictions, was in the national news last year over comments about gender.

He was ordained a bishop in the Ancient Church of the East in 2011 but established an independent church four years later in the Eastern Syriac tradition.

Meanwhile, Mr Albanese said a French construction worker who confronted the Sydney shopping centre knifeman is welcome to stay in the country as long as he likes.

Damien Guerot has been nicknamed “Bollard Man” on social media because of security camera footage showing him standing at the top of an escalator menacing Joel Cauchi with a plastic bollard as he approached. Cauchi fled down the escalator and people on Mr Guerot’s floor were kept safe.

Mr Guerot’s temporary Australian work visa was due to expire in July until the prime minister intervened.

“I say this to Damien Guerot, who is dealing with his visa applications, that you are welcome here, you are welcome to stay for as long as you like,” Mr Albanese said on Tuesday.

“This is someone who we would welcome becoming an Australian citizen, although that would of course be a loss for France,” he added.