One Chicago police officer was killed and a second was critically wounded when a prisoner who was receiving treatment opened fire inside Swedish Hospital in Chicago's Lincoln Square neighborhood Saturday morning, authorities said. The suspect was later arrested following a nearby standoff. 

In a news conference, Chicago Police Superintendent Larry Snelling said a 38-year-old officer and 10-year veteran of the department was killed in the shooting, which occurred at approximately 10:50 a.m. local time. A 57-year-old officer and 21-year veteran of the department was critically wounded. The officers were rushed to an area hospital, where one died, police said. No names were immediately released. 

Law enforcement sources told CBS News Chicago the prisoner had somehow managed to get hold of a gun and shoot the officers. 

The gunman then fled the hospital to a nearby home several blocks away, sources said. SWAT teams surrounded the home and later placed the suspect into custody. Snelling said that a third gun was recovered, but it was unclear where the weapon came from.

Snelling disclosed that the suspect had been originally arrested on suspicion of robbery, and he had been taken to Swedish Hospital for observation prior to the shooting. 

In a statement, Endeavor Health said that no hospital staff or patients were injured during the incident. 

"We are cooperating with law enforcement during their investigation and our deepest compassion remains with the officers and their families," Endeavor said.   

The shooting also prompted Chicago Alderperson Andre Vasquez to ask residents to shelter in place.