LITTLETON, Colo. — Hundreds of students at Columbine High School left class Wednesday to protest gun violence and honor the victims of the worst high school shooting since the Colorado massacre nearly 19 years ago.

A few of the roughly 300 students who joined the nationwide walkout held homemade signs, including some that said, “Enough is Enough.” They released red, white and blue balloons as the names were read of the 17 people killed a month ago at Marjory Stoneman Douglas High School in Parkland, Florida.

“This is Columbine and what happened is a tragedy and what happened at Parkland was also a tragedy,” said Leah Zundel, a 15-year-old sophomore. “And we cannot deal with kids having tragedies anymore who are afraid to go to school. Ever. We should never go to school in fear of our lives or in fear of anything.”

The teenagers also released balloons as the names of the 13 victims of the Columbine shooting in 1999 were read and then observed a moment of silence.

Columbine junior Kaylee Tyner said she and her fellow students have grown up watching more tragedies occur and asking why.

“We just want to show that students across America are standing with them and that it’s not only Florida that’s pushing for change, not only Parkland, that it’s everyone in America who is not just asking for change, but demanding it,” she said.

Unlike in Florida, Columbine students did not turn to activism in 1999, when the attack was seen as more of an aberration rather than part of a pattern. But Tom Mauser, the father of one of the slain students, campaigned for gun control. While lawmakers failed to require background checks at gun shows — where some of the weapons used in the attack were purchased — Colorado voters passed the requirement the following year.

Frank DeAngelis, who was principal of Columbine at the time of the massacre and attended the student protest, said adults haven’t done enough after each school shooting but he hopes they will listen to students now.

“We have this event one month after but they need to continue their fight to continue to be the voice for all students across the nation and across the world,” he said. “We see this too many times. Everybody is really passionate for about a month and then they forget.”

Elsewhere in Colorado, Marjory Stoneman students spoke to teens who walked out at Fairview High School in Boulder. Hundreds of students from some Denver schools also left class and walked to the state Capitol.

They cheered as Gov. John Hickenlooper addressed them with a bullhorn.

“The big part to remember, if you’re really going to succeed … and I have a feeling you might, you got to get involved in getting people elected. You’ve got to make sure that your voices are heard all the time,” the Democratic governor said.