Just a month after using rubber bullets, beanbag rounds and pepper spray to put down a riot outside a Dave Matthews Band concert, police in Hartford, Conn., reportedly used pepper spray on an unruly group of fans at a free hip-hop concert on Sunday night (9/5).

According to reports in the Hartford Courant, 400 to 500 people rushed the stage moments after headliner Ja Rule [ tickets ] began performing at a festival organized by radio station Jamz 910-AM dubbed the ''Back to School JamzSlam '99.'' The crush reportedly penned in about 10 officers, some of whom pulled out their batons to protect themselves.

Police told the newspaper that someone onstage -- possibly someone from the event's private security staff -- blasted an officer with pepper spray. Police reportedly then used their pepper spray to break up the increasingly agitated crowd. Ja Rule left the stage without finishing a single song, which caused some unhappy people in the crowd to begin hurling rocks and bottles at the stage.

While police defended the use of the spray, crowd members told reporters that things didn't get out of hand until police took an aggressive stand and angered the crowd.

About a dozen people were reportedly treated at local emergency rooms for minor injuries and released. Injuries included coughing due to exposure to the pepper spray as well as bumps and bruises. Police, who estimated a crowd of about 10,000, made no arrests.

Police also said that the incident wasn't nearly as serious as the melee outside of a Dave Matthews Band concert last month. That incident, which police said was fueled by alcohol and nitrous oxide, resulted in more than 40 arrests and dozens of injuries.