House Republicans on Tuesday decisively blocked a move by Democrats to debate a ban on assault weapons in Florida, six days after a massacre that took 17 lives at a Broward County high school.

The bill (HB 219), which would ban the sale and possession of semi-automatic weapons and high-capacity magazines like the kind used by confessed killer Nikolas Cruz, has been mired in a House subcommittee for months and has not been heard.

Amid rising tensions at the state Capitol, Democrats used a highly unusual procedure to move the proposal directly to the House floor for a debate and vote.

Republicans voted it down, 71 to 36. Several survivors of the massacre in Parkland, watching from the visitors' gallery, were overcome with emotion, and the action set off a firestorm of controversy on social media.

"How could they do that to us? Are you kidding me??? #Never again," Tweeted student Emma Gonzalez. "We are not forgetting this come midterm elections — the anger that I feel right now is indescribable."

The emotional flare-up at the Capitol came on a day when more than a hundred students from the school were headed to Tallahassee by bus to meet with Gov. Rick Scott, Attorney General Pam Bondi and legislative leaders.

Security in the Capitol was tighter than usual. On Wednesday, hundreds of people are expected to rally on the steps of the Old Capitol in support of additional gun restrictions in Florida.

Among those voting no were House Speaker Richard Corcoran, R-Land O'Lakes, a possible candidate for governor; three Republicans who are running for attorney general, Reps. Jay Fant, Ross Spano and Frank White; a candidate for agriculture commissioner, Rep. Matt Caldwell; Rep. Jason Brodeur, R-Sanford, whose wife is secretary of the state Department of Juvenile Justice; and the chairman of the Republican Party of Florida, Rep. Blaise Ingoglia, R-Spring Hill.

Democrats said the tragedy at Marjory Stoneman Douglas High School in Parkland created a new sense of urgency on the issue of easy access to assault weapons in Florida.

"I ask that you keep this bill and the conversation about the solution to combat mass shootings alive," said Rep. Kionne McGhee, D-Miami. "While this is an extraordinary procedural move, the shooting in Parkland demands extraordinary action."

HB 219 is sponsored by Rep. Carlos Guillermo Smith, D-Orlando, who personally knew some of the victims of the Pulse nightclub massacre in Orlando that claimed 49 lives in June of 2016.

When Smith tried to debate a proposed assault weapons ban on the House floor, Corcoran quickly cut him off, noting that under House rules, debate must be only about whether the bill should have been referred to three committees.

"You're on the substance of the bill," Corcoran told Smith.

While Republicans blocked any discussion of assault weapons Tuesday, they did debate at length another bill that declares pornography to be a public health risk.

That bill (HB 157), a largely symbolic resolution, is sponsored by Spano, who chairs the House Criminal Justice Subcommittee, the first committee assigned to hear the assault weapons ban.

"Porn is more important," Smith told reporters. "Has anyone had to bury their child because of pornography? He (Spano) has made that a priority above gun violence. He needs to own that."

Florida is the nation's largest swing state, but Republicans control the state House, 76 to 41, with three seats currently vacant.

Florida also allows 18-year-olds to purchase semi-automatic weapons, as Cruz did more than a year before the mass shooting at Stoneman Douglas High on Valentine's Day that claimed the lives of 14 students and three faculty members.