ST. PETER, Minn. (AP) — A top aide to Gov. Mark Dayton says more workers are being hired to improve staff security at the Minnesota Security Hospital in St. Peter.

Dayton chief of staff Jaime Tincher and several state lawmakers visited the psychiatric hospital on Tuesday after an assault left a counselor hospitalized with serious injuries.

In a statement, Tincher says she met with patients and workers, and will take what she learned to Dayton and Lt. Gov. Tina Smith.

Tincher also says the state Department of Human Services is hiring 20 additional security counselors and 24 other clinical and support workers to improve security of staff and quality of treatment. She calls those "important first steps."

The Star Tribune reports the state Occupational Safety and Health Administration is investigating the latest assault.