"At approximately 2:18 today [18:18 GMT], a male subject entered the VA hospital through the Taylor Street entrance. The individual was carrying an assault rifle and began firing. Within 30 seconds of that firing, the VA police responded and mitigated the threat. Nobody was hurt," Jeffrey Sallet said.
The name of the gunman and his motives remained undisclosed, but according to the acting hospital director, Lori Lohar, he was unlikely to be a veteran.
"The VA police were able to take the subject into custody without firing a shot," Sallet added.
He noted that shooting had occurred both inside and outside the hospital but did not say how many bullets had been fired.
Last November, a shooting that happened at another Chicago hospital, the Mercy Hospital and Medical Center, left four people, including the gunman, dead. The perpetrator reportedly fatally shot his ex-fiancee, who was on the medical staff, in the center's parking lot after arguing with her, and then walked into the building and opened fire at people inside.