ST. CLOUD, Minn. — An assault at the St. Cloud prison sent a corrections officer to the hospital.

Authorities say the sergeant was processing an offender through intake and was taking him to his residential unit when the inmate struck him in the face with an elbow. The officer was treated at the hospital and released.

The facility was locked down after Wednesday's attack.

The assault comes a week after the union representing corrections officers called for an increase in staff and changes to inmate discipline rules following a deadly attack on an officer at the Stillwater prison.