A bump stock, shown next to a .22-caliber rifle at a North Carolina gun shop in 2013. (Allen Breed/AP)

Maryland's top legislative leaders are backing a proposal to expand the state's automatic-weapons ban in 2018 by prohibiting the sale of bump stocks, a device used to accelerate the firing of semiautomatic weapons, including during last month's Las Vegas mass shooting.

Legislative aides for Senate President Thomas V. Mike Miller Jr. (D-Calvert) and House Speaker Michael E. Busch (D-Anne Arundel) said Wednesday that the lawmakers would support prohibiting sales of such mechanisms, a development first reported by the Baltimore Sun.

“There is no reason that bump stocks should exist,” Busch said. “Think of the number of people who could have been saved in Las Vegas if there wasn’t a bump stock.”

Sen. Bill Ferguson (D-Baltimore City) and Del. David Moon (D-Montgomery) have promised to introduce a bill next year to ban such devices, and Gov. Larry Hogan (R) said during a news conference Tuesday that it is “worth discussing doing something about bump stocks.”

On Monday, the U.S. Supreme Court declined to review a Maryland law that bans the sale of semiautomatic guns with certain military-style features. The law had been upheld by the U.S. Court of Appeals for the 4th Circuit.

Amy Hunter, a spokeswoman for the National Rifle Association in Maryland, said the organization thinks that bump stocks and similar devices “should be subject to additional regulations.” She did not respond to a request for comment on prohibiting sales of such items.

Jen Pauliukonis, the lead legislative advocate with Marylanders to Prevent Gun Violence, said she is “excited to have leaders in Maryland that take gun violence seriously and work toward policies that will make the public safer.”

She said her organization is anxious to see whether Hogan will move from a willingness to talk about bump-stock measures to backing a ban on such devices.

“There’s still an extra step, and hopefully he takes it,” she said.

If the legislature, which has large Democratic majorities in both chambers, passes a ban, Hogan’s stance on the issue could become a factor in his bid for a second term in 2018.

Maryland has some of the strictest gun laws in the nation, including a 2013 law that bars the sale of nearly all semiautomatic rifles and ammunition magazines that hold more than 10 bullets.

The proposal from Moon and Ferguson would not prohibit possession of existing bump stocks or the inheritance of such items if they have already been purchased legally. Moon said banning bump stocks and other devices that make semiautomatic rifles function more like fully automatic weapons would be “a common-sense response to uphold the spirit of existing laws in Maryland.”

In the Las Vegas shooting, which killed at least 59 people and wounded hundreds more, the perpetrator fitted at least a dozen guns with bump stocks, firing them at concertgoers from the 32nd floor of the Mandalay Bay Resort and Casino.