The Justice Department on Tuesday moved to implement President Donald Trump’s efforts to ban bump stocks, a gun modification that allows semiautomatic rifles to fire faster.

The new rule, which is expected to be published in the Federal Register in the coming days, will mandate that owners of bump stocks turn them in or destroy them. After the rule is published, members of the public will have 90 days to comply, meaning the devices will likely be outlawed officially sometime in late March.

The rule encourages people who currently possess bump stocks to destroy the devices themselves, but also says they’ll have the option to turn them over to the nearest Bureau of Alcohol, Tobacco, Firearms and Explosives office.

CNN first reported in November that the Justice Department was preparing to release new rules that would outlaw the gun attachments, citing officials familiar with the proposal. The devices will now be included under federal prohibitions for machine guns because bump stocks “allow a semiautomatic firearm to shoot more than one shot with a single pull of the trigger,” according to the new rule.

Matt Whitaker, the acting attorney general, said the ban would “continue to take illegal guns off of our streets” and praised Trump’s efforts to rein in the gun modifications.

“President Donald Trump is a law and order president, who has signed into law millions of dollars in funding for law enforcement officers in our schools,” Whitaker said in a statement. “We are faithfully following President Trump’s leadership by making clear that bump stocks, which turn semiautomatics into machine guns, are illegal.”

The plan has been in the works for most of this year after Trump first called for a ban on bump stocks in February after the shooting at Marjory Stoneman Douglas High School in Parkland, Florida, which left 17 people dead. A bump stock wasn’t used during that attack, but the gunman in an attack on a music festival in Las Vegas in October 2017 did use them.

Bump stocks are components, typically made of plastic, that replace standard rifle stocks and harness the firearm’s recoil to slide the firearm back and forth onto the shooter’s trigger finger, allowing it to fire like an automatic weapon.

With bump stocks attached to at least 12 of the rifles used in the Las Vegas shooting, the gunman killed 58 people, firing off about 90 rounds in 10 seconds, according to The New York Times, and more than 1,100 rounds over the course of the attack.

Some Democrats have remained skeptical about banning bump stocks via federal regulation, instead calling on lawmakers to pass new laws that ban not only the devices, but others that can increase the fire rate of semi-automatic weapons.

The acting director of the ATF has also warned that a federal regulation could prompt legal challenges, as the agency had previously determined that it did not have the authority to regulate bump stocks because they technically did not meet the definition of a “machinegun.” Critics from across the political spectrum have expressed similar concern, arguing that the administration’s move may ultimately be struck down in court.

The National Rifle Association, which expressed some support for the proposal last year after the Las Vegas massacre, said it was “disappointed” in the new rules, saying the group would have preferred if gun owners who already owned the devices were allowed to keep them.

Spokeswoman Jennifer Baker told The Associated Press that the rule “fails to address the thousands of law-abiding Americans” who complied with federal laws in the past.

Trump hinted in October that the ban was in the works, saying during a news conference that “we’re knocking out bump stocks” and that he had told the NRA “bump stocks are gone.”

“Over the next couple of weeks, I’ll be able to write it up,” Trump said at the time. He has remained a vocal supporter of Second Amendment rights.

State lawmakers moved more quickly to ban bump stocks, with 11 states passing legislation outlawing the devices in the year after the Las Vegas shooting. Four of those 11 bills were signed into law by Republican governors.

The inventor of the device, Slide Fire Solutions, said in April that it would stop selling bump stocks and shut down its website. Shortly after the Las Vegas shooting, sales of the attachment skyrocketed, and gun sellers said people were racing to buy them before a federal ban was put in place.