President Donald Trump announced he has ordered Attorney General Jeff Sessions to take steps to ban bump stocks, the type of gun modification that Las Vegas shooter Stephen Paddock used to kill 58 people in October.

“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,” Trump said Tuesday while speaking at a medal of valor ceremony at the White House. “I expect that these critical regulations will be finalized ... very soon.”

BREAKING: President Trump says he’s directed AG Sessions to clarify if bump stocks are illegal and to propose regulations to “ban all devices that turn legal weapons into machine guns.” pic.twitter.com/cnZ2mc08TF — NBC News (@NBCNews) February 20, 2018

“The Department understands this is a priority for the President and has acted quickly to move through the rulemaking process,” the DOJ said. “We look forward to the results of that process as soon as it is duly completed.”

Bump stocks are devices that allow a semiautomatic rifle to fire as quickly as a machine gun. The accessory replaces the firearm’s stock ― the piece that rests against the shoulder ― and harnesses its recoil to slide the gun rapidly back and forth onto the shooter’s trigger finger, firing each time.

Paddock was found to be in possession of more than a dozen assault-style rifles, many outfitted with bump stocks and 100-round magazines. He was ultimately able to fire more than 1,100 rounds in a period of 10 minutes.

In 2010 and again in 2012, the Bureau of Alcohol, Tobacco, Firearms and Explosives ruled that it did not have the authority to regulate bump stocks because they are not technically “machine guns,” which federal law defines as firearms that shoot more than one shot per pull of the trigger. As an executive agency, the ATF can’t officially make new laws. Instead, it’s limited to interpreting and enforcing acts of Congress ― in this case, gun control laws passed in 1934 and 1968.

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Justice Department officials said in December that they do not believe they could regulate bump stock sales without congressional action, according to The New York Times.

A bipartisan group of lawmakers introduced legislation to ban bump stocks and other similar accessories in the wake of the Las Vegas shooting, but the measure appeared to have stalled in recent months. Rep. Carlos Curbelo (R-Fla.), who sponsored one of the bills, said Trump’s announcement marked a “good step forward,” but called on House Speaker Paul Ryan (R-Wis.) to bring his proposal to the floor for a vote.

.@RepCurbelo: "Good first steps, but Congress must also act. That's why I teamed up with @sethmoulton to introduce #bipartisan legislation to ban #BumpStocks. Bring it to the floor @SpeakerRyan." - TC https://t.co/Oc9LnbxXrU — Rep. Carlos Curbelo (@RepCurbelo) February 20, 2018

Sen. Chris Murphy (D-Conn.), who sponsored a similar Senate bill, called the announcement a “small, but vital step.”

Sign after sign this week that we've hit a fulcrum point in this debate where politicians are, for the first time, scared on the political consequences of inaction on guns. Small, but vital step in the history of our movement. https://t.co/LVRAyPnzRp — Chris Murphy (@ChrisMurphyCT) February 20, 2018

ATF announced in December that it would explore the possibility of regulating bump stocks as machine guns, and asked the public to submit comments on the proposal. In the end, 85 percent of the more than 32,000 comments expressed opposition to such regulation, according to an analysis conducted by The Trace.

“I am directing the Department of Justice to dedicate all available resources to complete the review of the comments received, and, as expeditiously as possible, to propose for notice and comment a rule banning all devices that turn legal weapons into machineguns,” Trump said Tuesday in a statement.

A number of states and local jurisdictions have taken up the debate over bump stocks in the meantime. Massachusetts and New Jersey have both passed laws banning the devices. Several states, including Connecticut and Washington, as well as smaller municipalities, are also considering similar measures.

California and New York had banned the devices before the Las Vegas shooting.

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This article originally appeared on HuffPost.