OMAHA, Neb. (AP) — The Nebraska chapter of the American Civil Liberties Union is following through with its promise to sue the state prisons system because it hasn’t taken significant steps to remedy what the group calls inhumane conditions.

The ACLU filed a federal lawsuit early Wednesday on behalf of 11 prisoners. It names the Nebraska Department of Correctional Services, its director and various prison system officials.

The lawsuit blames prisoner overcrowding and dangerous understaffing for the deadly riots, staff assaults and escapes of recent years. The lawsuit takes the system to task for what it says is excessive use of solitary confinement and gross negligence of inmates’ medical and mental health issues.

The lawsuit, which seeks class-action status, asks for a court order to require state officials to fix those problems.