CAMERON, MO. -(AP) – A Missouri prison remains on lockdown more than a month after a protest turned into a riot, and officials with the union representing corrections officers worry that a staffing shortage could lead to more violence.

Inmate activities have been restricted at Crossroads Correctional Center in Cameron since May 12, when dozens of inmates angered by loss of programs and recreation time due to staffing shortages damaged dining halls, the kitchen and other property.

Corrections spokeswoman Karen Pojmann says the lockdown remains necessary because repairs and the investigation continue. Inmates get only sack meals and no phone calls or visits, other than with attorneys.

Tim Cutt of the Missouri Corrections Officers Associationsays inmate anger over restrictions borne out of staff shortages is boiling over. He worries it will get worse.