St. Cloud prison went on lockdown Thursday morning after an inmate attacked a corrections officer in the dining hall, causing a scuffle that injured three other responding officers.

The offender was immediately placed in restrictive housing, while all four Department of Corrections employees were evaluated at a hospital and released.

"This incident will be fully investigated, and the offender responsible will be held accountable under the law," said DOC spokeswoman Sarah Fitzgerald.

St. Cloud prison serves as the intake facility for the DOC, where offenders are processed and evaluated after being sentenced by the court. It houses approximately 1,050 adult inmates.

The latest assault comes at a challenging time for the department, following prison attacks that killed two corrections employees and injured more than a dozen others this year.

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.

DOC Commissioner Tom Roy will retire next week after eight years on the job. DFL Gov.-elect Tim Walz has appointed Paul Schnell, now the Inver Grove Heights police chief, to succeed Roy on Jan. 7. Schnell said he's committed to renewing focus on safety in the workplace.

"This administration pledges to do everything in our power to keep these brave correctional officers as safe as possible," Walz said last week. "Paul understands the importance of this work and how it ties directly to our efforts to seek justice, foster rehabilitation and reduce incarceration rates."

Schnell, 57, previously served as police chief in Maplewood and Hastings after holding a variety of posts at the St. Paul Police Department. He is now an adjunct faculty member at Metropolitan State University and the University of St. Thomas.

Though he has deep roots in law enforcement, legislators including Sen. Warren Limmer, R-Maple Grove, say they're concerned about Schnell's ability to sidestep to a different field.

In an interview with MPR News this week, Schnell stressed that he is keenly aware of the dangers associated with corrections work.

"These are realities that policing has faced for a long time. I understand the impacts of line-of-duty deaths on organizations and the people who do that work," he said. "The work they do is critically important to Minnesota."