A Catholic priest was stabbed in front of dozens of stunned worshippers as he was celebrating mass Friday morning at Montreal's St. Joseph's Oratory.

Montreal police said a 911 call was placed at around 8:40 a.m. When officers arrived at the landmark church, a male suspect was already detained by security guards.

Philip Barrett, who was sitting near the front of the church, said he saw a tall man, who appeared to be a Caucasian in his 30s, rise from a pew and quickly walk into the sanctuary to attack Rev. Claude Grou, the Oratory's rector.

"He walked over behind the altar and he seemed to strike the priest's body," Barrett said. "I think the priest fell down at that time. I do remember the priest was moving away from the man but it happened so quickly there was almost no time to react."

Barrett said people quickly restrained the suspect, who did not struggle. He said the suspect didn't speak or call out during the attack.

According to police, Grou was celebrating mass when a man suddenly approached him and attacked him with a knife.

Police spokeswoman Caroline Chevrefils says the victim suffered minor injuries to his upper body and was taken to hospital.

The Oratory later posted a message on Twitter that indicated Grou's life was not in danger, while inviting the public to pray for a prompt recovery.

The suspect was to be questioned by police Friday morning.

Barrett said Grou crumpled to the ground after the attack, but appeared to be conscious and alert about 15 minutes later when paramedics wheeled him to an ambulance.

He said members of the congregation immediately began praying, both for Grou and for the suspect.

St. Joseph's Oratory is among Canada's largest churches, and pilgrims from all over the world are drawn to its domed roof and stunning architecture.

Barrett said that he, like the rest of the roughly 60 people present, was shocked that an attack would happen in a place he has come to see as a haven.

"I really find it's a welcoming place," he said. "I just hope that as a result of this, I mean, I can imagine they're going to need more security, but I hope they can still keep that welcoming spirit."

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