Gunshots broke out at Forest High School in Ocala, some 38 miles south of Gainesville. One person was injured in the shooting, according to the Marion County Sheriff's Office.
Authorities have urged the public to avoid the area and asked parents to await further direction from the school on how to pick up their children.
The shooting took place in the school's main building. The wounded individual is a student at Forest High School who was transported to a local hospital with non-life-threatening injuries, according to Marion County Public Schools.
School district officials said it was not immediately clear whether the incident was intentional or accidental.
Around 2,200 students attend Forest High School. The students were evacuated and the high school placed on lockdown, along with 17 other schools in the area, according to Marion County Public Schools.
The shooting happened just minutes before thousands of students across the country were set to rally against school gun violence in an event called the National School Walkout. The event is taking place on the anniversary of the massacre at Columbine High School in Colorado, where two students opened fire in 1999, killing 12 classmates and one teacher.
However, one of the student organizers of Friday's walkout said the event is a direct response to the mass shooting in February at Marjory Stoneman Douglas High School in Parkland, Florida, which left 17 students and educators dead.
"The fact that this keeps on happening ... I knew I needed to do something," Lane Murdock, a sophomore at Ridgefield High School in Connecticut who helped organize the walkout, told ABC News.
ABC News' Emily Shapiro contributed to this report.
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