Just days ago, teenagers hid in the closets of their classrooms and saw their classmates, friends and beloved teachers die when a former student opened fire with an AR-15 at Marjory Stoneman Douglas High School in Parkland, Fla.

Now, these teenagers, most of whom are not old enough to vote yet, are organizing a march in Washington, D.C. and in other cities around the country on March 24 to call for stricter gun control legislation to prevent yet another mass shooting — at a school or elsewhere — from happening in the United States.

“My message for the people in office is this: You’re either with us or against us,” Cameron Kasky, a junior at the high school and organizer, told CNN on Sunday morning. “We are losing our lives while the adults are playing around.”

As politicians have offered messages of “thoughts and prayers” in the aftermath of another school shooting, the students who survived the massacre in Florida have responded with impassioned pleas for gun control and pointed criticism of politicians who have received political donations from the National Rifle Association. Called the “March for Our Lives,” the students are turning their traumatic experience into a rallying cry to hold the nation’s leaders accountable.

“How many more students are going to have to die and have their blood spilt in American classrooms trying to make the world a better place just because politicians refuse to take action?” asked David Hogg, a student who survived the shooting, in an interview with NBC’s “Meet the Press” on Sunday morning.

On Saturday, these students and others from surrounding schools participated in a gun control rally in Fort Lauderdale, where they carried signs that read “enough is enough” and “prayers and condolences are not enough.” In the days following the massacre, students around the country planned a national walkout on April 20, the 19th anniversary of the shooting at Columbine High School in Colorado that left 13 people dead.

Broward County Public Schools Superintendent Robert Runcie told NBC on Sunday he was proud of the students and their response to the horrific incident. “They are intelligent, they’re articulate, they’re passionate, and they’re committed to securing a safe future for themselves. This is their moment, this is their generation and they’re stepping up and doing what needs to happen,” he said. “I feel so encouraged that this time it will be different.”

Before the Stoneman Douglas students march on Washington, they’re heading to Tallahassee to speak to state leaders, Jaclyn Corin, a student who organized the visit, told NBC.

“We are the ones that looked into Nikolas Cruz’s eyes. We took 17 bullets to the heart. We are the only ones who can speak up,” Corin said. “We have to be the adults in this situation because clearly people have us failed us in the government, and we must make the change now because we’re the only ones who are going to.”

A website for the upcoming march notes that the goal is to have a comprehensive piece of legislation brought before Congress “immediately” to address gun issues in the country. “No special interest group, no political agenda is more critical than timely passage of legislation to effectively address the gun violence issues that are rampant in our country,” the march’s website said.

The student organizers of the upcoming march include Emma Gonzalez, whose passionate speech at Saturday’s protest made waves across the country. She has pointed to leaders like President Donald Trump, Florida Sen. Marco Rubio and Florida Gov. Rick Scott as ones who have received donations from the NRA.

“We already have pushed more than young children should possibly ever have to push, and these people who are being funded by the NRA are not going to be allowed to remain in office,” Gonzalez, who noted that high schoolers would soon become eligible to vote, told NBC on Sunday. “When Midterm Elections roll around, they’re going to be voted out of office. Incumbency rates are going to drop.”

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