WEST PALM BEACH, Fla. (AP) - More than a dozen inmates suffered minor injuries in a riot at Florida's maximum-security prison for girls and young women, which has struggled with staffing problems while trying to help severely troubled young people, authorities said.

Several girls were playing flag football at the Florida Institute for Girls on Sunday when three stripped off their clothes, said Darryl Olson, Department of Juvenile Justice regional director.

One of the girls grabbed a flag from the game, tied it around her neck and threatened to hang herself. The unrest quickly spread to all 48 inmates, with two fighting while others threatened to hurt themselves, scratched at their wrists or tried to open old wounds, authorities said.

Eleven of those injured were briefly taken to hospitals. Three inmates were committed to a mental health crisis unit.

When the institute opened in April 2000, it was praised as an innovative way to treat the state's most troubled and violent female offenders ages 13 to 21.

A grand jury investigation was launched in October reports of inappropriate sexual contact, improper use of physical restraints and long stays in isolation units. [Emphasis added] In February, the grand jury said allegations that officials covered up abuse were unfounded, but found several problems, including lack of staff training, massive turnover, persistent shortages and poor morale.

The three who started the unrest by stripping had recently returned from a mental health facility and might have been acting up to return there, Olson said. Some inmates prefer it to the prison.