PARKLAND —?In Washington, more than 2,000 high-school age protesters observed 17 minutes of silence outside the White House as part of a nationwide school walkout to protest gun violence.

An organizer counted down the seconds until 10 am and the protesters spent the 17 minutes sitting on the ground with their backs turned to the White House as a nearby church bell chimed.

The walkouts are the biggest demonstration yet of the student activism that has emerged following the massacre of 17 people at Marjory Stoneman Douglas High School on Feb 14 in Parkland, Florida.

Students were pouring out of Douglas High School in Parkland, Florida, as part of the nationwide school walkout against gun violence.

They walked out at 10 am and planned to stay out for 17 minutes, one for each victim of the shooting.

In an online livestream, David Hogg, a senior at the school who's become one of the public faces of protests against gun violence, criticized politicians for not doing more as he walked amid a mass of people.

Some students at an Ohio high school that had a shooting last year joined the nationwide student walkouts to protest gun violence, despite being warned they could face detention or more serious discipline.

The Springfield News-Sun reports about 10 students exited West Liberty-Salem High School as a group of supporters across the street cheered Wednesday.

Superintendent Kraig Hissong says campus isn't the place for political demonstrations and it's not in the district's interest to endorse political movements.

Students at Kell High School in Marietta, Georgia, were also warned against participating in the nationwide walkout. Police even patrolled outside the school. Nonetheless, three students walked out for the 17 minutes of the protest and then went back inside.

The group of Marjory Stoneman Douglas High School students shouted "MSD! MSD!" and engaged in a group hug Wednesday morning.

The high school students rallied to continue putting pressure on federal lawmakers to enact gun control legislation. The rally comes less than a week after Florida Gov. Rick Scott cited the students' actions in signing a bill that placed new restrictions on guns.

Police outside Atlanta patrolled Kell High School, where students were threatened with unspecified consequences if they participated in the nationwide walkout to protest gun violence.

A British couple walking their dogs went to the school to try to encourage students, but they were threatened with arrest by police officers if they didn't leave the campus in Marietta, Georgia.

Hundreds of students at Parkland High School, outside Allentown, Pennsylvania, walked out of class and headed to the auditorium for a rally dubbed #parklandforparkland.

That school and Marjory Stoneman Douglas High School in Parkland, Florida, share more than a name.

Stoneman Douglass freshman Daniel Duff, who survived the shooting by hiding in a closet but lost seven of his friends, is the cousin of Collin and Kyleigh Duff, who are brother and sister and go to Parkland High in Pennsylvania.

The Duff siblings have been selling #parklandforparkland bracelets, raising more than $10,000 for the Florida shooting victims, and Daniel Duff described what it was like to live through the shooting in a video that was shown at the rally.

Parkland High students called for stricter gun laws, read short biographies of each of the 17 shooting victims of last month's shooting and observed a moment of silence at 10 am.

Viacom is suspending all programming on its networks for 17 minutes as students across the nation walk out of school Wednesday to protest gun violence.

The suspension coincides with the National School Walkout, which started at 10 am. The company's networks include MTV, BET, Comedy Central and Nickelodeon, among others.

At East Chapel Hill High School in North Carolina, students were holding a session discussing gun violence in addition to joining students around the country in a walkout.

The students were wearing orange T-shirts emblazoned with an outline of the state and "#enough."Senior Talia Pomp was handing out the shirts. She said she was working to prevent a repeat of the school shooting in Parkland, Florida, last month that killed 17 people.

A superintendent says students at an Ohio high school that had a shooting last year could face school detention or more serious discipline for leaving class to protest gun violence in conjunction with nationwide student walkouts Wednesday.

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

The students in front of the White House chanted, "Hey, hey, ho, ho. The NRA has got to go!" and "What do we want? Gun control! When do we want it? Now!"Trump was traveling in Los Angeles and was not in the White House during the demonstrations.

Organizers say nearly 3,000 walkouts are planned in the biggest demonstration yet of the student activism.

The protests have drawn mixed reactions from school administrators. While some applaud students for taking a stand, others threatened discipline.

Some students say they don't care about the consequences, the issue is too important to remain silent.

Kara Litwin is a senior at Pope High School in suburban Atlanta. She says change never happens without backlash.