FILE - In this Oct. 4, 2017 file photo, a little-known device called a "bump stock" is attached to a semi-automatic rifle at the Gun Vault store and shooting range in South Jordan, Utah. The Trump administration... (Associated Press) 
 
 FILE - In this Oct. 4, 2017 file photo, a little-known device called a "bump stock" is attached to a semi-automatic rifle at the Gun Vault store and shooting range in South Jordan, Utah. The Trump administration is moving to officially ban bump stocks, which allow semi-automatic weapons to fire rapidly... (Associated Press) 
 
 FILE - In this Oct. 4, 2017 file photo, a little-known device called a "bump stock" is attached to a semi-automatic rifle at the Gun Vault store and shooting range in South Jordan, Utah. The Trump administration is moving to officially ban bump stocks, which allow semi-automatic weapons to fire rapidly... (Associated Press) FILE - In this Oct. 4, 2017 file photo, a little-known device called a "bump stock" is attached to a semi-automatic rifle at the Gun Vault store and shooting range in South Jordan, Utah. The Trump administration... (Associated Press) 
 
 WASHINGTON (AP) — 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. 
 
 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. 
 
 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. 
 
 The amended rule was met almost immediately with resistance from gun rights advocates, including Gun Owners of America, which said it would file a lawsuit against the Justice Department and ATF in order to protect gun owners from the "unconstitutional regulations." 
 
 "These regulations implicate Second Amendment rights, and courts should be highly suspect when an agency changes its 'interpretation' of a statute in order to impair the exercise of enumerated constitutional rights," the organization's executive director, Erich Pratt, said. 
 
 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. 
 
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 Associated Press writer Lisa Marie Pane in Boise, Idaho, contributed to this report. 
 
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 Follow Michael Balsamo on Twitter at www.twitter.com/MikeBalsamo1 . ||||| Justice Department Bans Bump Stocks, Devices Used In Deadly Las Vegas Shooting 
 
 Enlarge this image toggle caption Rick Bowmer/AP Rick Bowmer/AP 
 
 The Trump administration is banning bump stocks, the firearm attachment that allows a semiautomatic weapon to shoot almost as fast as a machine gun. 
 
 The devices, also known as slide fires, came under intense scrutiny after they were used by the gunman who opened fire on a country music concert in Las Vegas last year, killing 58 people. 
 
 The massacre touched off a public outcry, including from some lawmakers, for the accessories to be banned. 
 
 Under a new federal rule announced Tuesday by the Justice Department, bump stocks will be redefined as "machine guns" and therefore outlawed under existing law. 
 
 The new regulations, which were signed by acting Attorney General Matthew Whitaker, will take effect 90 days after being published in the Federal Register. A Justice Department official said that would likely happen Friday. 
 
 Current bump stock owners will have the 90 days before the new rule takes effect to either destroy the devices they own or turn them in to the Bureau of Alcohol, Tobacco, Firearms and Explosives. 
 
 Justice Department officials say they don't know exactly how many bump stocks are privately owned, but they estimate the number in the tens of thousands. 
 
 The move has met with mixed reactions from gun rights groups. In an emailed statement, the NRA said it is "disappointed" that the new rule doesn't include an amnesty, which would have allowed people who bought the attachments when they were still considered legal, to keep them. 
 
 Gun Owners of America went further, promising a lawsuit. In a statement, it called the administration's move "arbitrary," and an unacceptable reinterpretation of the federal laws against machine guns. In the past, the GOA has said that banning bump stock attachments could lead to the eventual banning of semi-automatic rifles. 
 
 Shannon Watts, founder of the gun control group 'Moms Demand Action for Gun Sense in America,' welcomed the rule, saying it may signal a new openness on the part of the administration to tighter firearms regulations. 
 
 "We're very hopeful that we can go in now, in January, and put forward something like a background check bill, a bill that would close the loophole that allows unlicensed gun sales without a background check," she says. "And have President Trump sign that into law." 
 
 But Watts says she would rather have seen bump stocks banned by an act of Congress, as some Democratic members of Congress proposed in the weeks after the Las Vegas massacre. 
 
 In previous years, federal firearms regulators ruled they could not ban bump stocks under existing federal law. Las Vegas caused the Trump Administration to order the ATF to review that decision. 
 
 The Justice Department followed up by proposing a federal rule change that would reclassify bump stocks so they fell under the definition of a 'machine gun,' as it's now doing. 
 
 Fully automatic machine guns are strictly controlled in the U.S. It is illegal under federal law for a private citizen to own a machine gun that was manufactured after 1986. 
 
 Regulators at the ATF have become increasingly preoccupied with vetting a wide variety of attachments for guns, some of them created with 3D printing technology. Last week the agency announced a policy requiring any new accessory needing evaluation to be submitted to the agency along with the firearm it's supposed to modify, to make it easier for the ATF to test it.
– The Justice Department says it is moving quickly with its review of "bump stock" devices after President Donald Trump directed the agency to propose regulations banning them, the AP reports. The devices allow semi-automatic rifles to fire faster and were used in last year's Las Vegas massacre. The Justice Department in December announced it was reviewing whether bump stocks are prohibited under federal law banning fully automatic weapons. The department said Tuesday it "understands this is a priority for the president and has acted quickly to move through the rulemaking process." Trump said Tuesday that he has signed a memo directing the Justice Department to propose regulations to "ban all devices" like the rapid-fire bump stocks. Seeking to show action days after a deadly school shooting in Parkland, Florida, Trump spoke during a White House ceremony recognizing bravery by the nation's public safety officers. "We must move past clichés and tired debates and focus on evidence based solutions and security measures that actually work," Trump said. White House officials say the president will be meeting with students, teachers and state and local officials to discuss ways of providing more school safety and address gun violence. Pressure has been mounting for action after the Parkland shooting.