Children's advocacy groups filed a federal lawsuit Wednesday that accuses a Mississippi juvenile correction center of subjecting young people to abusive conditions with prolonged isolation, verbal abuse and physical threats.

The Southern Poverty Law Center and Disability Rights Mississippi filed the lawsuit in U.S. District Court in Jackson against the Henley-Young Juvenile Justice Detention Center in Hinds County, one of the biggest such facilities in the state. The suit seeks class-action status.

The lawsuit claims, among other things, that people in the facility are denied mental health services and isolated in small cells for 20 to 23 hours a day, which the advocates said causes sensory deprivation.

When told about the allegations in the lawsuit, detention director Dale Knight said: "That's not true." He referred other questions to Hinds County Administrator Carmen Davis, who didn't immediately return a call.

The Henley-Young Juvenile Justice Detention Center is "based on semi-military style, which allows for constructive discipline of the incarcerated youth who have been accused of violating the law," according to a Hinds County website. It houses people aged 10-17.

Corrie Cockrell, a Southern Poverty Law Center attorney in the case, said the advocacy groups filed the lawsuit reluctantly after negotiations with the county came to a standstill.

The lawsuit seeks to ensure that youngsters in the facility are given the mental health treatment they need while being kept in humane conditions. Cockrell said she hopes the lawsuit will force Hinds County to send more youth to alternative community-based facilities that are not so restrictive.

"We just want to ensure that the children who have to go to this facility are afforded all of their fundamental rights and are not being abused," Cockrell said.