Students across the US walked out of their classrooms on Friday morning to demonstrate against gun violence.
Photo: AFP
The National School Walkout marked the 19th anniversary of the Columbine High School massacre in Colorado.
Connecticut high school pupil Lane Murdock set up the event in the wake of the Parkland shooting in Florida.
Only one hour before the walkout was due to begin, authorities said a student in Ocala, Florida was shot in the ankle at the Forest High School.
One teenager posted a photo of a barricade that his class constructed after hearing the gunshot.
Police and Marion County Schools officials said only one person - a 17-year-old student - was injured and a suspect is in custody.
The suspect was initially identified as a student, but authorities later clarified that he was not a current student at the school.
Students at Forest High School - which had planned to hold an in-school "civic demonstration" rather than a walkout - were taken to a nearby church to meet their parents.
Before midday, officers responded to reports of a gunman at another school in Marion County, but later said those reports were false.
However, all schools in the district were placed on "Code Red" lockdown as a precaution, according to district spokesman Kevin Christian.
The goal of Friday's demonstration, which involved more than 2,000 schools, was to raise awareness of gun violence and to combat political inaction.
Students from Washington-Lee High School in Arlington, Virginia join the National School Walkout April 20, 2018 in while marching to the U.S. Capitol in Washington, DC. Photo: AFP or licensors
Student, Lane Murdock, launched the National School Walkout campaign in the wake of the Parkland shooting in Florida.
The protest started as a petition on the website change.org and more than 250,000 people have signed it.
"I'm from Connecticut where Sandy Hook happened - I've been surrounded by this reality all of my life," she told the BBC, referring to the attack on an elementary school that left 26 dead.
Participants on Friday also held 13 seconds of silence, in honour of the 13 victims of the Columbine shooting.
The sample walkout agenda from the campaign says the students will not go back to school but instead will "make calls to their Senators' offices and flood social media with calls for reform".
US students already staged a national walkout on 14 March, one month after 17 people were murdered at Marjory Stoneman Douglas High School in Florida.
Major celebrities were also involved in the walkout.
Actors Robert DeNiro and Julianne Moore penned absence letters for students to explain why they were participating.
Students who survived the Florida shooting have actively advocated for an end to gun violence, with many backing legislative changes to control the sale of guns.
On Thursday, students from the Colorado school district where Columbine High School is located held a "Vote for Our Lives" rally adjacent to the scene of the massacre.
About 60 students from Parkland, Florida attended, as well as students who survived a 2013 shooting at nearby Arapahoe High School.
- BBC