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.
Speaking at the White House, Mr Trump said he had directed the Department of Justice to propose a law to make the accessories illegal.
The Republican president said that school safety was a “top priority” for his administration.
The gun control debate has been renewed by last week’s Florida school shooting.
Students and parents affected by that massacre, which left 17 dead, are planning a demonstration in the state capital of Tallahassee on Wednesday.
What did Trump say?
At an event on Tuesday recognising the bravery of law enforcement, Mr Trump said he had directed Attorney General Jeff Sessions to finalise new guidelines to declare bump stocks illegal “very soon”.
“The key in all of these efforts, as I said in my remarks the day after the shooting, is that we cannot merely take actions that make us feel like we are making a difference, we must actually make a difference,” he said.
“We must move past clichés and tired debates, and focus on evidence-based solutions and security measures that actually work and that make it easier for men and women of law enforcement to protect our children and protect our safety.”