Police said a choir lingered on the cathedral steps as the suspect entered the scene with two handguns and opened fire in the air.
Two NYPD officers and a sergeant arrived and opened fire, with the gunman hitting his head, a police source said. Officers who were on site at the time of the shooting were hired there for the concert.
“There was some kind of concert on the steps of the church,” NYPD spokesman Lt. John Crimbell told CNN. “There was a personal shooting. Officers at the scene involved him.”
Law enforcement sources told CNN that the gunman – a man in his 50s – was pronounced dead at St Luke’s Hospital on Sunday afternoon.
NYPD Police Commissioner Dermat Shia praised the officers as heroes during a press conference on Sunday.
Two semi-automatic rifles were recovered from the scene with a bag believed to belong to the suspect containing petrol, wire, rope, several knives and a Bible, Shia said.
According to several witnesses at the scene, the suspect was shouting “Kill me,” Shia said.
“Fortunately, none of the participants were affected,” Isadora Wilkenbelt, a spokeswoman for St. John the Divine Cathedral, said in a statement. “The much-needed afternoon of our choir gift, song and solidarity to New York City was lessened by this shocking act of violence. We will be strong together and act as a safe haven for prayer and meditation.
He said two of Brewer’s staff – his chief executive and press secretary – were present during the shooting, but were unharmed.
The NYPD will continue to review body camera footage and the incident is under investigation, Shia said.
Correction: An earlier version of this story misrepresented the singers. They lingered on the church steps before the shooting.
CNN’s Ala Elasar contributed to this report.