Last Updated Mar 14, 2018 7:06 PM EDT
Students at thousands of schools across the country Marjory Stoneman Douglas High School in Parkland, Florida, last month.to protest gun violence. The 17-minute walkout is a tribute to the 17 victims who were fatally shot at
According to the Say #Enough website, which compiles the stories of shooting victims and advocates for change, there will be more than 3,000 walkouts held in communities coast to coast and in Puerto Rico. Students participating in the movement left or were leaving their classes at 10 a.m. in their respective time zone.
Students from 28 schools in Washington D.C., Maryland and Virginia marched to Capitol Hill, extending their protest, while inside lawmakers grilled officials from the ATF and FBI on how they proposed to tackle safety in schools in the wake of the school massacre. They gathered where just the day before, 7,000 pairs of children's shoes were placed outside Capitol Hill to represent the children killed by guns since.
As a crowd of lawmakers gathered to joing them, the first student speaker, Matt Post, started his speech by urging students to refuse compromise measures. "We will not sit in classrooms with armed teachers," Post said. "We will not learn in fear."
Post said that students should not settle for anything less than comprehensive gun control reform, and urged students and others to vote out legislators who failed to act. Almost immediately after Post's line on gun control, the National Rifle Association tweeted out a defiant message in defense of the second amendment.
Snapchat's "Snap Map" feature, meanwhile, showed a vast number of walkouts Wednesday, with students sharing their experiences at gatherings around the country. At 12 p.m. ET, schools further west, including Columbine High School in Colorado, began walking out. None of the current students in Columbine would have been born at the time of the notorious mass shooting there, which resulted in 15 deaths in April 1999.
In Broward County, Florida, where the Parkland massacre took place, public schools superintendent Robert Runcie said students who walk out of class would not be disciplined for leaving. He said teachers should make this a "teachable moment."
CBS News correspondent Adriana Diaz reports Stoneman Douglas students walked out to the football field. School officials said they want students to exercise their First Amendment rights in a safe environment that's supervised by adults.
However, some schools across the county, including a group in Pennsylvania, hesitated about participating in Wednesday's walkout.
Stoneman Douglas student David Hogg, who has been an outspoken advocate of gun control since the shooting, spoke with CBSN about the significance of Wednesday's walkout.
"I'm feeling happy to know that this has stayed in the national media and to know that people are taking action," Hogg said. "To know the fact that we all are standing up as Americans is a huge deal to know, and it means a lot just that we're coming together and working hard to change this issue."
"The goal here is just to make sure our legislative leaders know that their actions are going to be held accountable to them and that there will be ramifications for either what actions they have had or what inactions they had," he said before referring to the date that marks two months since the shooting. "How many other mass shootings are we going to have to have? ... I'm worried about what's going to happen after April 14. That terrifies me."
Since the shooting on Valentine's Day,and a new state gun law for the first time in 22 years, but student activists want to see changes nationwide.
On Tuesday, prosecutors said, 19-year-old Nikolas Cruz.