Updated April 21, 2018 07:19:47

Thousands of students have walked out of classes across the United States, marking the 19th anniversary of the massacre at Columbine High School with a show of unity aimed at pressuring politicians to enact tighter gun restrictions.

Students from more than 2,600 schools from Florida to Chicago started streaming out of their classes in the latest round of gun-control activism following the February shooting at a high school in Parkland, Florida.

At 10am in each time zone, students at dozens of schools left class to take 13-seconds of silence honouring the 13 victims at Columbine.

From there, some students headed to rallies at their state capitol buildings, while others stayed at school to discuss gun violence with organisers allowing students to control their own local protests.

Photo: Following the 13-seconds of silence, students joined protests at government buildings. (Reuters: Brendan McDermid)

Many of the demonstrators wore orange, a colour that has come to represent the movement against gun violence.

"I'm trying to get an education, but I still have a small fear that someone will come in with a gun," said Ayanna Rhodes, 14, who walked out of Washington International School to join hundreds of local students in front of the US Capitol.

"It's an issue that's been in this country for a long time."

David Hogg: 'We have to stop this'

Two gunmen went on a shooting rampage at the Colorado high school in 1999, leaving 12 students and a teacher dead before killing themselves.

The massacre stunned the nation but since then, school shootings have become commonplace.

Columbine has not held classes on April 20 since the massacre, a district spokeswoman said, so there would be no walkout at the school.

Students were encouraged to take part in community service.

But even as students prepared for their protest on Friday morning, news began trickling out that one person was wounded in a shooting at a high school near Ocala, Florida.

The latest incident unfolded about 360 kilometres north-west of the Parkland high school, where two months ago a former student killed 17 people in the deadliest high school shooting in US history.

At Marjory Stoneman Douglas High School, student David Hogg said the latest shooting underscored the urgency of the protests.

"We have to stop this. We're not going to be able to stop this unless we continue to make our voices heard, though, when our elected officials won't," Mr Hogg said in a video posted to social media.

"We have to get out there and make our voices heard, not as Democrats or Republicans, but as Americans."

Despite widespread revulsion over the recent Parkland school shootings, the issue of gun control remains sensitive across the country, where the Second Amendment of the Constitution guarantees the right to bear arms.

'I should be worried about grades, not guns'

Students walked out of high schools in New York, Detroit and Washington, among hundreds of other cities and towns.

Of the students that walked out across the country, many were waving placards with slogans such as "Enough is enough", "No more gun violence" and "I should be worried about grades, not guns".

Outside the White House, scores of young protesters sat in silence while they listened to the names of gun violence victims read aloud.

The walkouts, speeches and drive to sign up voters were aimed at pressuring US politicians to enact more restrictions on gun sales in the run-up to November's midterm congressional elections.

Carlos Rodriguez, a 17-year-old junior from Marjory Stoneman, travelled to Columbine for the anniversary, and said he found a sense of solidarity in the outpouring of support.

"That's the only thing that's keeping us Douglas students alive right now: the distraction of fighting for our rights and advocating for our lives," Mr Rodriguez said.

"It's the one thing keeping us hopeful, it's the one thing keeping us from not being able to sleep at night."

The latest national rally came more than a month after tens of thousands of students from some 3,000 schools participated in the #ENOUGH National School Walkout to demand that politicians seek tighter gun control regulations.

It also followed March For Our Lives rallies in cities across the United States on March 24 that were some of the biggest US youth demonstrations in decades, with hundreds of thousands of young Americans and their supporters taking to the streets to demand tighter gun laws.

It was not immediately clear whether Friday's turnout would match those of the earlier protests.

AP/Reuters

Topics: activism-and-lobbying, community-and-society, law-crime-and-justice, murder-and-manslaughter, united-states

First posted April 21, 2018 06:07:15