Shortly after 4:30 p.m. ET, NBC News reported an active shooter situation near Mercy Hospital in Chicago. Chicago Police have stated there are multiple victims.

CBS Chicago confirmed a gunman has opened fire on the hospital’s campus.

5:07 PM (Eastern) Update: Anthony Guglielmi, Chicago Police’s Chief Communications Officer, reports that at least one “possible” offender has been shot. A Chicago police officer has also been hit and is in critical condition.

9:40 PM (Eastern) Update: Three people are reportedly dead, including the police officer who was shot by the gunman. The two other victims were hospital employees, a doctor and a pharmacy assistant.

The suspected gunman is also dead, however it is not yet known if he was killed by police or if he took his own life.

The Associated Press has more details about what led up to the shooting:

[Chicago Police Superintendent Eddie] Johnson says the shooting began outside the hospital with a “verbal altercation” in the parking lot between people who knew each other. A friend tried to intervene and the suspected gunman pulled up his shirt and showed a weapon. Gunfire erupted and the shooter ran inside the hospital, where police confronted him.

He says that one of the women killed was in a domestic relationship with the gunman.

This story is developing and will be updated.