US President Donald Trump has signed an order to ban bump-stock devices, which were used by a gunman who killed 58 Las Vegas concert-goers last year.
Such devices enable a rifle to shoot hundreds of rounds a minute.
Speaking at the White House, Mr Trump said he had directed the justice department to propose a law to make the accessories illegal.
The gun control debate took on a new urgency after 17 people were killed at a school in Florida last week.
Students and parents affected by the massacre at Marjory Stoneman Douglas High School are planning a demonstration in the state capital of Tallahassee on Wednesday.
Some of them arrived on Tuesday in time to see the state legislature reject a proposed ban on assault weapons and large capacity magazines. However it will consider a package of more limited gun restrictions.
In all around 100 students, spread across three buses, made the journey of more than seven hours to the state capital.
For many of these students, it is their first time to the capitol building in Tallahassee – much less to lobby their lawmakers over a national issue.
There is an excitement among the students, who sense that they may be on the cusp of starting a national movement.
“We’re travelling to our state capital to make sure that none of these people that we grew up with – that we’ve known our whole lives – die in vain,” Julia Salomone, 18, said confidently.
So how do the students expect the politicians to receive them? “Honestly, I feel like they’re gonna be overwhelmed by us because they’re going to see in our faces our determination, our commitment to this, because this is all we’re fighting for right now,” 16-year-old Rain Valladares said. “They’re gonna look us in the face and see that we’re not gonna back down.”
In December, the Bureau of Alcohol, Tobacco, Firearms and Explosives began considering a regulation for bump stocks, opening a process that drew more than 35,000 public comments.
Proposals to ban bump stocks have been put forward with mixed results at state level, including in South Carolina, Illinois, Washington and Colorado.
Whether the bureaucratic review process just initiated by the president will amount to a comprehensive ban on bump stocks depends very much on how the yet-to-be-written regulation is crafted.
Still, it is the closest the Trump administration has come to new firearm regulation after multiple mass shootings – and, perhaps, a reflection of the new pressure the president is feeling on the gun issue.
Congress, of course, could have stepped in at any point in the five months since the Las Vegas massacre and banned bump stocks without this contorted bureaucratic process. The National Rifle Association, however, is not keen on seeing a bipartisan coalition forming to enact any kind of new federal gun control laws.