Four people have died as the result of a shooting at Chicago‘s Mercy Hospital, the city’s medical examiner said.
The victims include a police officer, a doctor and a pharmacy assistant.
The suspected gunman also died in the incident, police said, although it wasn’t immediately clear if he took his own life or that responding officers killed him.
WATCH: Police respond after reported shooting near Mercy Hospital in Chicago
Chicago Police Supt. Eddie Johnson said the incident began with a “verbal altercation” in the hospital parking lot between people who knew each other.
The suspected gunman pulled up his shirt and showed his weapon at one point, before running inside the hospital, where he was confronted by police.
One of the victims was a woman who was in a domestic relationship with the gunman. It’s not clear whether she was the doctor or the pharmacy assistant.
A witness named James Gray told reporters that the gunman appeared to be “shooting people at random.”
A woman named Maria Correa told the Associated Press that she hid under a piece of furniture, clutching her four-month-old son for 10 to 15 minutes as the violence unfolded. She said she heard at least eight shots.
Those “were the worst minutes of our lives,” she said.
A woman who works in a bicycle shop near the hospital said she heard several gunshots with pauses in between. She said that at one point, she heard five shots in quick succession, but that the gunshots stopped after police arrived.
WATCH: Coverage of Chicago hospital shooting and reaction
The hospital said in a tweet just before 5:50 p.m. ET that the shooting incident was over, the hospital secured and patients safe.
Police have not commented on a possible motive for the shooting.
Earlier, police had warned people to avoid the area surrounding the hospital, explaining that a “heavy police response” was incoming.
Television footage showed several people, including some wearing white coats, walking through a parking lot with their arms up.
WATCH: Chicago’s Mercy Hospital shooting: Procession held in honour of fallen officer
Police were seen shepherding people away from the hospital and onto buses, according to video broadcast by ABC7 news channel.
Chicago Mayor Rahm Emanuel and Chicago Police Supt. Johnson were monitoring the incident, authorities said.
Mercy Hospital has a rich tradition as Chicago’s first charter hospital. Founded in 1852, the hospital treated both Union soldiers and Confederate prisoners of war, according to its website.
— With files from Reuters and the Associated Press