Rubio reiterates support for 'red flag' laws after facing heat from 'March for Our Lives' students

"I've been in politics for a while, so attacks are just part of politics. People can judge whether they're fair or not. I'm not worried about me," he told CNN in an interview. "I do worry there are people out there who have views and decided not to get engaged in politics or speak out because we want to shout them down. And both sides do that. That's not good."

Rally participants, both on stage and in the audience, heavily criticized Rubio on Saturday for not distancing himself from the National Rifle Association a little over a month after a gunman killed 17 people at Marjory Stoneman Douglas High School in Parkland, Florida.

Rubio said he's spoken with some students from the same high school who feel differently about how to address gun violence than students who've been leading the recent movement.

"They're afraid to be attacked or stigmatized," he said, speaking to CNN after an event on the child tax credit that he advocated for in the tax reform bill.

At "March for Our Lives," students brandished orange price tags with "$1.05" -- a figure student activists said represents the total amount of money Rubio has accepted from the NRA divided by the total number of students in Florida.

"So, this is how much we're worth to the Florida government. It's our price tag," Marjory Stoneman Douglas freshman Lauren Hogg said as she showed off the tag at the rally in Washington.

A Washington Post examination of Federal Election Commission data indicates that as far as donations go, Rubio has received only $4,950 directly from the NRA in his career and returned a further $9,900. However, the NRA, like other outside spending groups, can spend an unlimited amount of money benefiting a candidate by running ads for them or against their opponents.

Rubio said Monday he hadn't seen the price tags but described the protest symbols as "political speech" that citizens have a right to make. Asked if the recent shooting and the ensuing student-led movement had caused him to re-analyze the NRA, Rubio said "no."

"I support the Second Amendment and they're one of the groups that support the Second Amendment, so I would expect that they would be supportive of people that support the Second Amendment," he said.

Not all Parkland students have been targeting Rubio, however. Kyle Kashuv, also a student at Marjory Stoneman Douglas, said this weekend that he has spoken with Rubio on the issue of gun violence.

"He cares so much about this. And it pains me to see how he's being represented in the media," he said on CBS' "Face the Nation."

Rubio has been one of the few Republicans to take center stage on working toward some kind of gun-related provisions. At a CNN town hall just days after the shooting, Rubio faced angry constituents frustrated with Congress for failing to pass gun control laws after repeated school shootings over the past decade. Rubio, at the event, said he would support raising the age requirement from 18 to 21 for rifles and shotguns -- something the NRA opposes -- and said he would consider supporting a ban of high capacity magazines.

He later teamed up with fellow Sen. Bill Nelson, D-Florida, to introduce a bill that would encourage states to adopt "red flag" laws, which give officials authority to take guns away from people who pose a threat to themselves or others. He was also a co-sponsor of a school safety bill that funds more security measures in schools. And he supported the "Fix NICS" bill, which aims to improve the National Instant Criminal Background Check System.

Both the school safety bill and Fix NICS were passed in last week's massive spending bill.

During the interview Monday, Rubio repeatedly pointed to his red flag bill, despite opposition from some staunch gun rights supports, saying since the measure was adopted in Florida, "three dangerous people have had their guns taken from them after due process."

"And who knows what it's prevented as a result of it," he added.

Rubio said the best way to stop a shooter is to take preventative action, even if that means "removing guns from them before they can do anything, all of their guns, not just their rifles, everything. That's what works best."

"And if this killer had been dealt with before he even stepped foot in that school -- as he should have been -- we wouldn't ... have had this tragedy," he continued. "We need to be better at doing that."

Students at the rally made elections a central point of their calls for action, urging voters ahead of the midterm elections to oust lawmakers who didn't do enough to address gun violence. Asked whether he thinks their calls will have an impact in November, Rubio noted there are millions of voters who hold different views and they'll be voting as well.

But he stressed a sense of urgency in the matter.

"Between now and November, there could be another shooting, so we shouldn't wait 'til November to act. Let's figure out what we can all agree now and do those things," he said. "But I certainly don't want to wait until November to act."