Chicago hospital shooting leaves four dead, including police officer and gunman

The two women killed were a doctor and a pharmaceutical assistant, Mayor Rahm Emanuel confirmed.

A police spokesman said the gunman had died in an exchange of shots, but it is not clear if he took his own life.

A second officer avoided injury after a bullet fired in his direction became lodged in his gun, police say.

Officials say the gunman appeared to target a woman with whom he was in a relationship but they do not suggest a motive.

"Chicago lost a doctor, pharmaceutical assistant and a police officer, all going about their day, all doing what they love," said Mr Emanuel. "This tears at the soul of our city. It is the face and the consequence of evil."

The incident occurred at Chicago's Mercy Hospital at about 3pm local time on Monday.

Police say it started with a row in the car park between people who knew each other.

The gunman first shot the woman he apparently knew and then headed inside the building, closely followed by several police officers. More shots were fired, apparently at random.

Mercy Hospital was quickly evacuated during the incident as armed police descended on the scene.

The hospital later confirmed that police were able to secure the area, ensuring the safety of dozens of patients.

Other images from the scene showed people rushing outside the facility, including some staff in uniform.

US media named the doctor killed as Tamara O'Neal.

Police confirmed that an officer named Samuel Jimenez had died in hospital of his injuries.

"Those officers who responded today saved a lot of lives," said Police Superintendent Eddie Johnson.

"A woman who got off the elevator, she did nothing and he just shot her. We just don't know how much damage he was prepared to do."

The officer who was shot at but escaped injury during the incident shared images of a bullet embedded in the side of his gun, Chicago news broadcaster ABC7 reported.