The Trump administration moved Tuesday to officially ban bump stocks, which allow semi-automatic weapons to fire rapidly like automatic firearms, and has made them illegal to possess beginning in late March.
The devices will be banned under a federal law that prohibits machine guns, according to a senior Justice Department official.
Bump stocks became a focal point of the national gun control debate after they were used in October 2017 when a man opened fired from his Las Vegas hotel suite into a crowd at a country music concert below, killing 58 people and injuring hundreds more in the deadliest mass shooting in modern U.S. history.
WATCH: From October 2017: Washington Mulls Bump Stock Ban
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Washington Ponders Ban of Rifle Accessory Used by Las Vegas Shooter
The regulation, which was signed by Acting Attorney General Matthew Whitaker on Tuesday morning, will go into effect 90 days after it is formally published in the Federal Register, which is expected to happen on Friday, the Justice Department official said.
The official wasn't authorized to discuss the matter publicly ahead of the regulation's formal publication and spoke to the AP on condition of anonymity.
In March, President Donald Trump said his administration would "ban" the devices, which he said "turn legal weapons into illegal machines."
Shortly after the president's comments, the Justice Department announced that it had started the process to amend federal firearms regulations to define bump stocks as machine guns. The Bureau of Alcohol, Tobacco, Firearms and Explosives sought public comment on the proposal, drawing more than 35,000 comments.
FILE - An example of a bump stock that attaches to a semi-automatic rifle to increase the firing rate is seen at Good Guys Gun Shop in Orem, Utah, U.S. on October 4, 2017.
The amended regulations reverse a 2010 ATF decision that found bump stocks did not amount to machine guns and could not be regulated unless Congress changed existing firearms law or passed a new one. In the aftermath of the Las Vegas shooting, there was a growing push by some members of Congress to ban bump stocks, but no legislation was passed. At least 10 states have sought their own restrictions on the devices.
People who own bump stocks will be required to either surrender them to the ATF or destroy them by late March, the official said. The change has undergone a legal review and the Justice Department and ATF are ready to fight any legal challenge that may be brought, the official added.
Police said the gunman in the Las Vegas massacre, Stephen Paddock, fired for more than 10 minutes using multiple weapons outfitted with target scopes and bump stocks. Paddock fatally shot himself after the shooting and there were 23 assault-style weapons, including 14 fitted with rapid-fire "bump stock" devices, strewn about the room near his body on the floor of his 32nd-floor hotel suite at the Mandalay Bay casino-hotel.
The largest manufacturer of bump stocks, Slide Fire Solutions, announced in April that it was going to stop taking orders and shutting down its website. The remaining stock of the devices is now being sold by another company, RW Arms, based in Fort Worth, Texas.