Braden River High School and the Manatee County Sheriff's Office are investigating threats involving the high school.
Two calls alleging a threat were reported through FortifyFL Wednesday.
FortifyFL is a reporting tool that allows students and community members to anonymously report information about alleged threats involving schools.
In a message Braden River High Principal Carl Auckerman sent to parents Thursday morning before school, he notified parents that the Sheriff's Office and School District of Manatee County security are aware of the threat.
There is an increased security presence in and around Braden River High Thursday, according to the message.
Auckerman encouraged parents to speak to their students about the seriousness of making any threats against a school.
"Any threat made against our school or students can lead to life-altering legal and school district consequences," he said in the message.
Mike Barber, the director of communications and family and community engagement, said threats are not uncommon and the School District of Manatee County averages one threat per week.