Washington (CNN) The Trump administration plans to announce the long-anticipated federal rule officially banning bump stocks in the coming days, according to US officials familiar with the matter.

Bump stocks gained national attention last year after a gunman in Las Vegas rigged his weapons with the devices to fire on concertgoers, killing 58 people. President Donald Trump vowed to outlaw the devices soon after the tragedy, and some lawmakers on Capitol Hill urged him to back a permanent legislative fix.

But opposition from lawmakers and the National Rifle Association ultimately made a regulatory change the only realistic path forward to accomplishing the President's goal.

The devices make it easier to fire rounds from a semi-automatic weapon by harnessing the gun's recoil to "bump" the trigger faster -- an operation that caused officials at the Bureau of Alcohol, Tobacco, Firearms and Explosives during the Obama administration to conclude that it's merely a gun accessory or firearm part, not subject to federal regulation.

At Trump's direction, however, the Justice Department submitted a proposed final rule earlier this year that upended the Obama-era interpretation, and concluded that bump-fire stocks, "slide-fire" devices, and devices with certain similar characteristics all fall within the prohibition on machine guns by allowing a "shooter of a semiautomatic firearm to initiate a continuous firing cycle with a single pull of the trigger," and therefore, they are illegal under federal law.

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