COLUMBIA, S.C. (AP) — A maximum security prison in Columbia has been placed on lockdown after two inmates attacked two prison employees.

Department of Corrections spokeswoman Sommer Sharpe said the assault happened Friday at the Broad River Correctional Facility.

Sharpe says the two prison employees who were attacked were taken for medical treatment and released Friday night.

She did not release any additional information on what led to the assault or how long the prison will be on lockdown. She says the prisoners and employees are all safe.

Sharpe says the incident is under investigation and no charges have been filed yet. She did not release the names of the inmates.