OAK PARK HEIGHTS, Minn. - A corrections officer is recovering after what the Department of Corrections (DOC) is calling a 'serious' attack at the maximum security facility at Oak Park Heights.

A DOC release says the on-duty sergeant was seriously attacked by an offender this morning, fought back and was then assisted by a full force of correctional officers that responded to the emergency. At this point injuries suffered by the officer are considered non-life threatening.

The facility remains under lockdown in the wake of the incident.

DOC says the unnamed offender is serving a life sentence for aiding and abetting 2nd degree murder. Upon completion of the investigation it is expected that new charges will be filed against him.

"In the face of a very difficult day, the other corrections officers are honoring their colleague by continuing to do their jobs with professionalism," read a DOC statement. "This is a reminder of the difficult job our corrections officers do every day to keep Minnesotans and our prisons safe."