US President Donald Trump has said that his administration would take steps to outlaw an accessory that enables a rifle to shoot hundreds of rounds a minute.
The White House added he may consider other firearms restrictions after last week's school shooting in Florida.
Nikolas Cruz, a former student at the Marjory Stoneman Douglas High School, opened fire with an AR 15-style assault rifle and killed 17 poeple.
"Just a few moments ago I signed a memorandum directing the attorney general to propose regulations to ban all devices that turn legal weapons into machine guns," Mr Trump told a White House event.
The move would bypass Congress, where legislation to ban "bump stocks" has failed to advance since last October's mass shooting in Las Vegas.
US President @realDonaldTrump says he has directed the Attorney General to ban gun modification devices like the "bump stocks" used in the Las Vegas mass shooting pic.twitter.com/cgOVpSJYGf
— Brian O'Donovan (@BrianOD_News) February 20, 2018
It puts Trump at odds with powerful gun rights groups like the National Rifle Association that previously opposed efforts to ban them.
The president's announcement came shortly after White House spokeswoman Sarah Huckabee Sanders said he would consider raising the minimum age for buyers of the assault-style rifle used last week by 19-year-old Cruz in the fatal Florida shooting.
Yesterday, the White House said that Mr Trump also supported legislation that would tighten the national criminal background check system for gun buyers.
Those steps fall far short of what gun-control advocates have called for but would mark a change in course for Mr Trump, who courted the support of gun rights groups during his 2016 presidential bid and has loosened gun ownership rules since taking office.
Fifty-nine people were killed in the Las Vegas shooting, the deadliest mass shooting in modern US history.
The gunman, Stephen Paddock, began shooting from the 32nd floor of a hotel during a country music festival for several minutes, before taking his own life.
Following the shooting, US police recovered firearms, explosives and a cache of ammunition at his home.
