The extent of the victims’ injuries was not immediately known and there were no additional details about the person who was in custody following the shooting about lunch time (early this morning AEST) on the Florida State University campus.

The person was not authorised to publicly discuss details of the ongoing investigation and spoke to the Associated Press on condition of anonymity.

At least six people have been hospitalised, including one person in a critical condition, a spokesperson for Tallahassee Memorial HealthCare said. The other patients were in a serious condition, the spokesperson said.

Ambulances, fire trucks and patrol vehicles from multiple law enforcement agencies raced toward the campus that sits just west of Florida’s state capital after the university issued an active shooter alert midday Thursday, saying police were responding near the student union.

“Our prayers are with our FSU family and state law enforcement is actively responding,” Governor Ron DeSantis wrote on X.

Hundreds of students streamed away from the direction of the student union.

Students were glued to their phones, some visibly emotional, while others hugged each other. Dozens gathered near the music school waiting for news.

Ryan Cedergren, a 21-year-old communications student, said he and about 30 others hid in the bowling alley in the lower level of the student union after seeing students running from a nearby bar.

“In that moment, it was survival,” he said.

After about 15 minutes of hiding, university police escorted the students out of the union and he saw a person getting emergency treatment on the lawn, he said.

Junior Joshua Sirmans, 20, was in the university’s main library when he said alarms began going off warning of an active shooter.

Law enforcement officers escorted him and other students out of the library with their hands over their heads, he said.

Attorney General Pam Bondi said in a social media post that the Justice Department is in touch with FBI agents who are on the scene.

Students and faculty were instructed to seek shelter and await further instructions.

“Lock and stay away from all doors and windows and be prepared to take additional protective measures,” the alert said.