SIOUX FALLS, S.D. (KELO) -- The South Dakota State Penitentiary and Jameson Annex in Sioux Falls went into lockdown status at 11:30 Sunday night. The Department of Corrections isn't saying what led up to the higher security measure. According to a release from the Department of Corrections, the length of the lockdown is unknown. During the lockdown, phone service will be managed for inmates.All visits are canceled during this time. However, attorney visits won't be affected, according to the release. One parent who has a son in prison told us today by phone that the lack of communication is frustrating for the families. We checked with the Attorney general's office today. They say the cases against the inmates are currently making their way through the court system and range from aggravated assault to reckless burning and property damage. What you need to know about whooping cough In July there was unrest at the Mike Durfee State Prison in Springfield. The Department of Corrections called it a fight, and said six people were injured. The inmates told us it was a gang war and blamed a lack of supervision because they claim the prison is understaffed. Information on the current lockdown in Sioux Falls is limited to a release from the Department of Corrections. The last line reads in part.. "Because this is related to facility security and operations, we will not be responding to further questions and inquiries during the lockdown." The latest count from the Department of Corrections puts the prisoner count at the state penitentiary at 772 inmates.