Tense scenes have erupted at a church where a Christian bishop and three churchgoers were stabbed by a man during a televised service in western Sydney.
A large police response, including special response teams, was under way on Monday night after a man was arrested in Wakeley following reports of multiple people being stabbed.
"Officers arrested a male and he is assisting police with inquiries," police said in a statement.
An angry mob of hundreds descended on the church where riot police forcibly moved the crowd on after police cars were smashed.
Police said they were still working to restore order hours after the stabbing, as a helicopter flew overhead urging the crowd to leave the area.
It came after a man dressed in black approached Mar Mari Emmanuel, the Assyrian Orthodox bishop at Christ the Good Shepherd Church.
The man is seen stabbing the bishop multiple times to the head and upper body at the altar as parishioners screamed and ran to the cleric's aid.
The man remains in police custody at an undisclosed location away from the church
.NSW Premier Chris Minns said the scene was disturbing but urged calm.
"My thoughts and prayers are with the victims and first responders who are working to keep us safe," the premier said.
"It's important that the community remain calm and continue to listen and act to the directions of Police and Emergency Services.
"We are a strong community in NSW and it's important that we all stick together, particularly in the face of adversity."
NSW Ambulance said they were called to the church about 7.15pm and sent multiple paramedics to the scene.
A spokesman said they had treated a man in his 50s for multiple cuts before taking him to Liverpool Hospital.
A man his 30s was also treated for lacerations and taken to hospital.
A man in his 20s was being treated for a cut to his hand and a man in his 60s treated for a laceration to his arm at the scene.
The church said Bishop Emmanuel and a senior priest were in a stable condition and also appealed for calm.
"We ask for your prayers at this time," the church said in a statement posted on social media.
"We also kindly ask anyone at the church to leave in peace as our Lord and Saviour, Jesus Christ, teaches us."
The Ahmadiyya Muslim Community said it was it profoundly saddened and shocked about the brutal attack on Bishop Emmanuel.
National President and Grand Imam of the Ahmadiyya Muslim Community Inamul Haq Kauser said the community unequivocally condemned the attack in the strongest possible terms.
"We extend our deepest sympathy to all those injured in the attack and wish them a speedy and complete recovery."
The attack comes two days after Sydney and the nation was left reeling by a stabbing rampage at Westfield Bondi Junction that killed six people.
Joel Cauchi was shot dead during the rampage on Saturday, which also injured seven people including a baby girl.
