SIOUX FALLS, S.D.(KELO)- Two prison guards at the South Dakota Penitentiary are recovering from injuries after being assaulted by two inmates.

Kyle Jones and Lester Monroe face charges of first degree attempted murder, aggravated assault and simple assault.

Both inmates have a history of violent offenses, so if they’re convicted, Attorney General Marty Jackley says they could face prison sentences of up to 100 years.

Video evidence shows the inmates punched one of the officers in the head 70 times in just over a minute.