Students across the US are walking out of their schools to demand action on gun violence following last month’s massacre in Florida.

More than 3,000 walkouts were planned across the US and around the world, organisers said.

Students were urged to leave class at 10am local time for 17 minutes — one minute for each victim in the February 14 attack at Marjory Stoneman Douglas High School.

Thousands of students gathered on Pennsylvania Avenue in front of the White House, holding signs and cheering in support of gun control.

The students chanted, “Hey, hey, ho, ho. The NRA has got to go!” and “What do we want? Gun control! When do we want it? Now!”

Students during a 17-minute walkout protest at the Stivers School for the Arts in Dayton, Ohio (AP Photo/John Minchillo)
Students during a 17-minute walkout protest at the Stivers School for the Arts in Dayton, Ohio (AP Photo/John Minchillo)

President Donald Trump was in Los Angeles at the time.

Stoneman Douglas High senior David Hogg livestreamed the walkout at the tragedy-stricken school in Parkland, Florida, on his YouTube channel.

Walking amid a mass of people making their way onto the football field, he criticised politicians for not taking more action to protect students.

He said the students could not be expected to remain in class when there was work to do to prevent gun violence.

“Every one of these individuals could have died that day. I could have died that day,” he said.

From Florida to New York, students poured out of their schools, marching through the streets or gathering on campus to demonstrate.

Some schools applauded students for taking a stand or at least tolerated the walkouts, while others threatened discipline.

The co-ordinated walkout was organised by Empower, the youth wing of the Women’s March, which brought thousands to Washington last year.

Although the group wanted students to shape protests on their own, it also offered them a list of demands for politicians, including a ban on assault weapons and mandatory background checks for all gun sales.

“Our elected officials must do more than tweet thoughts and prayers in response to this violence,” the organisation said on its website.

Other protests planned in coming weeks include the March for Our Lives rally for school safety, which is expected to draw hundreds of thousands to the nation’s capital on March 24.

Another round of school walkouts is planned for April 20, the 19th anniversary of the Columbine High shooting in Colorado.

Some students in Massachusetts said that after Wednesday’s protest, they planned to rally outside the Springfield headquarters of the gun maker Smith & Wesson.

The walkouts drew support from companies including media conglomerate Viacom, which planned to pause programming on MTV, BET and all its other networks for 17 minutes during the walkouts.

Districts in Sayreville, New Jersey, and Maryland’s Harford County drew criticism this week when they said students could face punishment for leaving class.

In suburban Atlanta, one of Georgia’s largest school systems announced that students who participated might face unspecified consequences. Some vowed to walk out anyway.

Police in the Atlanta suburb of Marietta patrolled Kell High, and at least three students walked out anyway. A British couple walking their dogs went to the school to encourage students but were threatened with arrest if they did not leave.

About 10 students left West Liberty-Salem High School in Ohio — which had a shooting last year — despite a warning they could face detention or more serious discipline.

“Change never happens without backlash,” said Kara Litwin, a senior at Pope High School in Cobb County, Georgia.

The possibility of being suspended “is overwhelming, and I understand that it’s scary for a lot of students,” said Lian Kleinman, a junior at Pope High.

“For me personally, this is something I believe in. This is something I will go to the ends of the Earth for.”

Students from Westglades Middle School support the nationwide protest against gun violence (AP Photo/Lynne Sladky)
Students from Westglades Middle School support the nationwide protest against gun violence (AP Photo/Lynne Sladky)

Other schools sought a middle ground, offering “teach-ins” or group discussions on gun violence.

Meanwhile, free speech advocates geared up for a battle, with the American Civil Liberties Union issuing advice for students who walk out.

It said schools cannot legally punish them more harshly because of the political nature of their message.

In Pennsylvania, Wisconsin and Texas, some lawyers said they would provide free legal help to students who are punished.