(CBS/AP) The Justice Department filed a civil rights lawsuit Thursday against the state of Mississippi, alleging abuse of juvenile offenders at two state-run facilities. Some youths were tied to poles or forced to eat their own vomit, prosecutors said.

The suit was filed in U.S. District Court for the Southern District of Mississippi. R. Alexander Acosta, assistant attorney general for civil rights, said negotiations between federal and state officials failed to address the problems identified in a year-long federal investigation of the Oakley Training School in Raymond and the Columbia Training School in Columbia.

Oakley houses about 325 boys and Columbia houses about 200 boys and girls. Most are non-violent offenders. The average stay is two to three months.

Among the abuses uncovered: suicidal girls were stripped naked and placed in solitary confinement in a dark cell with only a drain for a toilet, boys were forced to run with mattresses strapped to their backs, girls who threw up while running in the heat were forced to eat their vomit, and youths were tied to poles or hog-tied.

"This is no way to set juvenile offenders on the course to law-abiding and productive lives," Acosta said.

Of 33 investigations of state-run juvenile facilities, nursing homes and other institutions nationwide, this is the first time the Justice Department felt the need to ask the federal courts to intervene, he said.

"Given the nature and the pattern of the violations identified, we believe that a remedy backed by the authority of the federal judiciary is necessary," Acosta said.

Acosta said that both facilities have less than two-thirds of the needed staff and the shortages have prevented state officials from dismissing abusive employees.

According to a June letter from the Justice Department to Mississippi Gov. Ronnie Musgrove, investigators found the camps also lacked proper sanitation and educational services, and violated the youths' First Amendment rights by "forcing them to engage in religious activities."

The letter said youth were sometimes forced to get up in the middle of the night and walk around their dormitory with their hands on their head. Counselors were reported to have slapped and choked youths, and used pepper spray on them when they refused to exercise, or when they were tied up.

"These exercises and disciplinary practices serve no penological or rehabilitative purpose. Many are cruel and demeaning," the letter read.

During the late 1980s and 1990s, youth offender facilities — sometimes called "boot camps" — became a popular method for deterring young lawbreakers from future crimes. A 2000 Justice Department census of the criminal justice system found 36 youthful offender facilities throughout the country.