A wing of Stillwater prison was placed on lockdown Wednesday morning after an inmate assaulted a sergeant, the first such attack under a new administration committed to bolstering safety for state Department of Corrections officers.

A prisoner targeted the sergeant in the B-East living unit late Wednesday morning. "Our corrections officers responded quickly and professionally and contained the incident," said DOC spokeswoman Sarah Fitzgerald.

The officer was evaluated at a hospital and later released. One living unit in the high-security facility will remain locked down while the incident is investigated, Fitzgerald said.

It marks a troubling trend of officer assaults inside Minnesota prisons following attacks that led to the deaths of two corrections employees and injured more than a dozen others last year. Most recently, four officers were injured during a scuffle at St. Cloud prison Dec. 29 after an inmate attacked a colleague in the dining hall.

The union representing corrections officers is pushing the Legislature to hire 327 more officers amid charges of increasingly low morale. The current climate has made recruiting and retaining officers difficult, union leaders say.

Stillwater, in particular, has seen many of the most violent episodes. Last July, officer Joseph Gomm was bludgeoned to death with a hammer by an inmate working in the prison's metal fabrication program. In the weeks following his attack, 30 officers staged a protest by refusing to work there until management installed more security cameras and allocated additional staffing.

The agency ultimately relented and eliminated the industry program, added cameras and required guards to work in pairs when monitoring large groups in that space.

Newly appointed DOC Commissioner Paul Schnell, who succeeded Tom Roy on Monday, has said he's committed to renewing focus on safety and security in the workplace.

Schnell, 57, previously served as police chief in Inver Grove Heights, Maplewood and Hastings after holding a variety of posts at the St. Paul Police Department.