This is a developing story. SIOUX FALLS S.D. (KELO)-- The South Dakota State Penitentiary and Jameson Annex in Sioux Falls have been placed on lockdown status as of 11:30 Sunday night. According to a release from the Department of Corrections, it is unknown how long the lockdown will last. During the lockdown, phone service will be managed for inmates. All visits are cancelled during this time. Attorney visits won't be affected, according to the release.