The gunman, wearing a white medical lab coat, stalked two floors of the Bronx-Lebanon Hospital Center, in the New York borough of the Bronx, and tried to set himself on fire before police searching the building found him dead of a self-inflicted gunshot, Police Commissioner James O’Neill said.

One female physician was shot to death, and six other people were wounded, five seriously, including one who was shot in the leg, O’Neill said at a news conference.

Mayor Bill de Blasio characterized the shooting as an “isolated incident” that appeared to be “a workplace-related matter.” He said that it was “not an act of terrorism.”

“One doctor is dead, and there are several doctors who are fighting for their lives right now amongst those who are wounded,” de Blasio told reporters. “This is a horrific situation unfolding in the middle of a place that people associate with care and comfort.”

O’Neill said the gunman was armed with an assault rifle.

Neither the mayor nor police immediately identified the suspect or any of the victims. O’Neill said the gunman was a former employee of the 972-bed hospital.

Bronx Borough President Ruben Diaz, in an interview with WABC News, identified the gunman as Dr. Henry Bello and said he had been fired by the hospital. Other media reports said Bello was 45 years of age.

The New York Times and the New York Daily News reported, citing unnamed sources, that Bello had resigned from the hospital rather than face termination over accusations of sexual harassment.