Chicago, IL – Police responded to an “active shooter” and reports of shots fired at Mercy Hospital in Chicago.

Chicago police confirmed that one officer had been shot and was being transported to University of Chicago Hospital in critical condition, WCIU reported.

Although details of the incident were not yet clear, witnesses said they heard multiple gunshots from inside the hospital, and then saw a huge police response to the scene just after 3:20 p.m. on Monday afternoon, WLS reported.

Chicago Tribune reporters at the scene said there were reports that the shooter was down, but police have not yet confirmed that information.

Chicago Police Spokesman Anthony Guglielmi tweeted “reports of multiple victims” in the attack, but police have not yet released any confirmed number of victims.

A Chicago Fire Department spokesman told the Chicago Tribune that fire officials had called an emergency medical services Plan II which sent at least 10 ambulances to the scene in response to the “active shooter” situation.

A witness at Mercy Hospital captured video of police responding into the building, and shared it on Twitter.

She later tweeted video of a messy crime scene inside the hospital.

A hospital employee told the Chicago Tribune that she was working in her office when a lockdown message was sent out over the hospital’s public address system.

She said employees were evacuated and put on city buses as police dealt with the active shooter in the hospital.

“I don’t know what happened,” she said.

“They told us to run so we did,” another hospital employee told the Chicago Tribune.

Police have asked the public to avoid the area, and the hospital’s emergency room has been shut down for ambulance traffic.

This is a developing story and we will keep you updated. For all of our updates, follow us on Facebook and go to your news feed preferences under your settings, then select that you want to see more of Blue Lives Matter posts in your news feed. Otherwise, Facebook may not show you updates.