COLLEYVILLE (CBSDFW.COM/AP) – Another wave of student protests disrupted classes Friday across North Texas and the country as part of the National School Walkout. Young activists at thousands of campuses left their classrooms to press for tougher gun laws.

The date of the protests was chosen to line up with the 19th anniversary of the Columbine High School shooting, which left 13 people dead in Littleton, Colorado. Students on Friday gathered for moments of silence honoring the victims of Columbine and other school shootings.

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Organizers planned walkouts in every state, with more than 2,600 schools registered on the event’s website as of Thursday. After the walkouts many students headed rallies at statehouses while others stayed on their campus to discuss gun violence or hold voter registration drives.

This follows the wave of youth activism that has emerged after the February shooting massacre at Marjory Stoneman Douglas High School in Parkland, Florida. Tens of thousands of students left class in March to protest gun violence, in what historians called the largest youth protest movement since at least the Vietnam War.

Plans for Friday’s walkout began hours after the Parkland shooting, when Connecticut teen Lane Murdock started a petition.

“We’re walking out to remember every single young person who has been killed by American gun violence,” stated Murdock, a sophomore. “We’re walking out to talk about the real problems our country is facing, and the solutions that our leaders are too scared to dream up.”

The National School Walkout aims to hold elected officials accountable, promote solutions to gun violence, and demystify and engage students in the political system. Organizers have emphasized that this is intended to be a nonpartisan event focused on preventing further gun violence.

Colleyville Heritage High School was among the North Texas schools participating in Friday’s walkout, and had the support of the Grapevine-Colleyville Independent School District. Officials said that students who participated will not face disciplinary action. The district worked with the school and its students to find an appropriate way to protest.

The walkout at Colleyville Heritage High School began at 11:10 a.m. and last for 17 minutes, one minute for each victim of the Parkland shooting. The time was near the end of a class period. The jointly planned event was meant to be impactful, respectful and constructive, all while not causing a major disruption to studies.

“Seeing how the students responded to it was inspiring,” said Colleyville Heritage High School student Anastasia Diakonis.

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Lake Highlands High School in Dallas, Lakeview Centennial High School in Garland and Centennial High School in Frisco also participated on Friday, along with additional campuses in Dallas, Mansfield, Richardson and Celina.

But not all parents are on board with the walkouts. “I understand the reason behind them doing it,” added Colleyville Heritage High School parent Robert Williams. “It’s for a good cause, but then there’s also other ways to do it and go about getting your point across.”

Administrators at many schools tacitly allowed the walkouts in March, opting not to punish participating students. But some now say that the leniency has expired. “You don’t need to be out of school all day to make your voices known,” said chancellor Richard Carranza with New York City’s education department. “I’m going to ask you to stay in school.”

Still, students at many New York City schools are planning to rally at Washington Square Park.

Those who do choose to participate have the support of one of America’s biggest movie stars. Robert DeNiro penned an excuse letter — like a permission slip that a parent would sign for a teacher — sharing several legitimate reasons that someone would be absent from class for the walkout.

Some schools in Houston, and elsewhere, gave students time to share their views, but warned them not to leave their campuses or return to classes late. Other schools scheduled alternative events for when classes were over. But many schools simply said students were expected to stay in class throughout the day.

Here in North Texas, the Keller Independent School District also asked students to remain in their classes Friday. The request came after a threat was made at Keller High School, forcing the district to increase campus security and cancel a pep rally. The nature of the threat is not known. Students in Keller did not participate in Friday’s event.

Meanwhile, in the Allen Independent School District, students who participated in the walkout will be disciplined “according to the student code of conduct,” explained chief information officer Tim Carroll. They will be marked absent, but there will be no additional penalties unless a student has an excessive amount of absences already.

There will be no walkout at Columbine High School, which has long canceled classes on the anniversary of the shooting.

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It was April 20, 1999 when two students walked into Columbine High School in Littleton, Colorado carrying guns, bombs and ammunition. They killed 12 students and one teacher, and injured another 23 people. After a gunfight with police, the gunmen both committed suicide in the school’s library. It is still one of the worst mass shootings in U.S. history.