Panic and fear gripped another Florida school Friday when a gunman opened fire, wounding one student before being taken into custody on a day planned for a national classroom walkout to protest gun violence, authorities said.

It happened Friday morning at Forest High School, which was put on lockdown, the Marion County Sheriff’s Office reported. The wounded student, a 17-year-old boy, was taken to a local hospital for treatment of a non-life threatening injury to his ankle.

Some students and teachers piled desks and filing cabinets against classroom doors as a makeshift barricade.

Police initially said the 19-year-old suspect is also a student at the school, but later said he was a former student not currently enrolled. No charges were immediately announced. The sheriff’s office said no other schools in the county were under any threat.

The Ocala shooting comes just over two months after a gunman killed 17 people and wounded 17 others at Marjory Stoneman Douglas High School in Parkland, Florida. Nikolas Cruz, 19, faces the death penalty if convicted in that Valentine’s Days shooting.

The shooting also coincided with a nationwide student walkout to protest gun violence on the anniversary of the 1999 massacre at Colorado’s Columbine High School. The Ocala school had planned its version of a walkout, students said.

Chris Oliver told the Ocala Star-Banner that his 16-year-old son, a Forest student, told him the shooting happened near his classroom. The boy told Oliver the shooter was standing in a hallway and fired at a closed classroom door. The shooter then dropped what authorities said was a shotgun, ran and tried to hide, the boy told his father.

Craig Ham, deputy superintendent of Ocala schools operations, said the gunman carried a shotgun in a guitar case into the school by blending in with students. Ham told reporters the shooter fired at the bottom of a classroom door, which was locked, and pellets struck the victim in the ankle.

Jake Mailhiot’s psychology class had just begun Friday morning when school officials announced a “code red” alert over the intercom.

“You could hear in their voice that this wasn’t a drill,” the 16-year-old junior said.

Students and teachers had been prepared for such alerts and leapt into action to barricade the classroom’s one door and block the door’s window.

“Our teachers started pushing file cabinets and desks toward the door, and a few friends and I joined in,” Mailhiot said. “We also started tying together some jackets to hang out the window, in case we needed another way out.”

In a photograph Mailhiot shared on social media, the classroom door is invisible behind a tall pile of furniture.

Mailhiot said about 15 people in the classroom waited over 30 minutes to be evacuated by Ocala police. They were instructed to leave the room with their hands up, he said.

The school had planned to participate around 11 a.m. in a walkout commemorating the Columbine shooting. Mailhiot said he had hesitated to participate in the walkout because he was worried the large crowd outside the school would present a large target for anyone waiting to cause a disturbance.

“I worried if something was to happen, that’s where it would happen,” Mailhiot said.

Marion County schools Superintendent Heidi Maier decided six weeks ago that any students who walked out would be punished. Instead, Maier instructed the seven mainstream high school principals to meet with their school’s student body to develop a topic of discussion for a 30-minute session. All such events were canceled Friday.

Marion County Sheriff Billy Woods praised the quick response by the school resource officer, as well as school personnel and first responders. In the Parkland shooting, school resource officer Scot Peterson retired amid accusations he did not do enough to confront the Stoneman Douglas gunman.

The Forest resource officer, Marion County Sheriff’s Deputy James Long, “did not hesitate. He went right in,” Woods said at a news conference.

Woods said Long heard a “large, loud banging sound” and immediately responded. Long “recognized what we had at that time,” he said.

The sheriff said the suspect was not injured, was not fired at and was arrested without resistance.

“Marion County does everything to protect their children,” Woods said.

After the shooting, all students were taken by bus with a police escort to First Baptist Church of Ocala, where parents gathered to pick them up, officials said.

Rachael Carter was at the church waiting to be reunited with her daughter, a 10th-grader who turned 16 this week. Carter’s pastor called her when he saw a post on social media.

“I’m shaking like a leaf in a hurricane,” Carter said.

She that once she is reunited with her daughter, she will “stick to her like Velcro.”

Students who saw anything related to the shooting were separated so they could be interviewed by investigators.

School district spokesman Kevin Christian sent a recorded phone message urging parents to stay away from the school.

Ocala police, the sheriff’s office, the Florida Highway Patrol and the FBI were investigating. They divided into teams that cleared all buildings, vehicles and the parking lot area. Once all students were off campus, authorities began conducting a more methodical search of the campus.

Forest High has an enrollment of more than 2,000 students, according to the National Center for Education Statistics.

(AP)