RELATED: What we know about the doctor who opened fire inside NYC hospital
Shots rang out at about 2:55 p.m. on the 16th floor at Bronx-Lebonon Hospital, located in the Bronx.
Police said a former employee at that hospital -- who sources have identified as 45-year-old Dr. Henry Bello -- opened fire with an assault rifle, injuring six people on the 16th floor.
The gunman then went up to the 17th floor, police said, where he shot and killed a woman before trying to set himself on fire. The hospital's sprinklers were activated during this time, knocking down the fire.
PHOTOS: Images from the scene
It's at this point that the gunman apparently shot and killed himself. Police found him lying on the floor with the assault rifle nearby. He was also wearing a white medical-type coat at the time, which was apparently used to conceal the rifle before the shooting.
New York City Mayor Bill de Blasio said the woman killed was a doctor, and some of those wounded are also doctors who "are fighting for their lives."
Watch the mayor's full remarks here:
Of those injured, five have serious injuries and one was shot in the leg. All were taken to the hospital's emergency room for treatment.
The mayor added that this appears to be a workplace dispute and not an act of terror.
RELATED: Witnesses recount horror inside deadly Bronx hospital shooting
People inside the hospital took cover, blocking off door access and taking cover. Someone inside the hospital posted this photo showing a barricaded door.
People were seen leaving the hospital with their hands up, being led out by police.
The FBI confirmed this shooting does not appear to be terror-related:
NYPD is handling Bronx shooting. At this time there is no nexus to terrorism; we are monitoring situation. @NYPDnews— FBI New York (@NewYorkFBI) June 30, 2017
The ATF said it was sending agents to assist with the situation:
BREAKING: ATF New York special agents are responding to assist @NYPDnews partners at the Bronx-Lebanon Hospital shooting incident.— ATF HQ (@ATFHQ) June 30, 2017
Stay with ABC7 News for the latest details on this developing story.