MILWAUKEE (CBS 58) -- Milwaukee police are investigating after a security guard at Ascension Columbia St. Mary's on Milwaukee's east side was stabbed Monday morning, Jan. 29. 

It happened just after 6 a.m. at the hospital's emergency department on Lake Drive and North Avenue. 

Officials say an 18-year-old man was arrested and the 47-year-old victim was treated for non-fatal injuries. 

In a statement, an Ascension Wisconsin spokesperson said:

"Early this morning, there was a security incident in the Emergency Department at Ascension Columbia St. Mary’s Hospital - Milwaukee Campus. One of our security guards was injured during an altercation with an individual who entered the Emergency Department. The security guard was treated for their injuries and has been released. Milwaukee Police were on scene almost immediately and took the individual into custody. We are cooperating with MPD on their investigation. The ER remains open. Safety is our top priority and we would like to thank everyone who worked together to ensure the safety of our patients, visitors, associates and providers."

Criminal charges will be referred to the Milwaukee County District Attorney's Office in the upcoming days.